Standalone L2 Processing and Control Architecture in 5G Flexible RAT Systems

ABSTRACT

Logical channel (LCH) may be multiplexed together based on one or more latency requirements. Mapping of LCH(s) to spectrum operating mode(s) (SOM(s)) may be based on SOM capability and/or LCH requirements. A WTRU may determine mapping based on one or more pre-defined rules. The mapping may be based on one or more requirements for the various type of traffic and/or SOM capabilities. A radio bearer may be mapped to one or more SOMs. The WTRU may be configured with a set of SOMs, for one or more, or each, radio bearer. The WTRU may dynamically determine, for example based on radio conditions, buffer status and/or other parameters, the SOM to use. Incompatible multiplexing of LCH may be reduced and/or avoided, perhaps based on using one or more transport blocks (TBs) mapped to the same physical layer (PHY). Traffic may be prioritized based on one or more latency requirements.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. Pat. Application No.16/089,960, filed Sep. 28, 2018, which is the National Stage entry under35 U.S.C. § 371 of Patent Cooperation Treaty Application No.PCT/US2017/024568, filed Mar. 28, 2017, which claims the benefit of U.S.Provisional Pat. Application No. 62/315,165, filed on Mar. 30, 2016, thecontents of which being hereby incorporated by reference as if fullyset-forth herein in its respective entirety, for all purposes.

BACKGROUND

Mobile communications are in continuous evolution and is already at thedoorstep of its fifth incarnation - 5G. As with previous generations,new use cases largely contributed in setting the requirements for thenew system. It is expected that the 5G air interface may enable improvedbroadband performance (IBB), industrial control and communications(ICC), vehicular applications (V2X, V2V) and/or massive machine-typecommunications (mMTC).

Deployments of a 5G network may include stand-alone systems, and/or mayinclude a phased approach, e.g., in combination with existingdeployments and/or with existing technologies (e.g., such as LTE and/oran evolution thereof). Combinations with existing technologies mayinvolve radio access network components and/or core network components.For initial deployments using a phased approach, it may be expected that5G systems may be deployed under the umbrella of an existing LTE system.In this LTE-Assisted deployment scenario, an LTE network may providebasic cellular functions such as mobility to/from LTE, core networkfunctions and so on. As commercial 5G deployments may become moreavailable, it may be expected that the deployments may evolve such thatthe 5G systems become standalone, perhaps independent of LTE. Thissecond phase of 5G may be expected to target new (e.g., heretoforeundefined) use cases with perhaps stringent reliability and/or latencyrequirements.

SUMMARY

Functionality of a 5G protocol stack may be provided. The functions ofthe protocol stack may include one or more of: header compression,security, integrity protection, ciphering, segmentation, concatenation,(de-)multiplexing, automatic repeat request (ARQ), mapping to spectrumoperating mode (SOM), modulation and/or coding, hybrid-ARQ (HARQ),and/or mapping to antenna/physical channels. A wireless transmit andreceive device (WTRU) may be configured with a (e.g., single) HARQentity and/or one or more, or multiple, SOMs. The WTRU may have a (e.g.,single) HARQ buffer to manage for the HARQ signals received across theSOMs. The WTRU may be configured to transmit/receive traffic of variouskinds over the SOMs. A WTRU may be configured with at least one HARQentity for one or more, or each, SOM configured. The logical channels(LCH(s) may be assigned to any of the SOMs.

Logical channel(s) may be multiplexed together based on latencyrequirements. Mapping of LCH(s) to SOM(s) may be based on SOM capabilityand/or LCH requirements. The WTRU may determine mapping based onpre-defined rules. The mapping may be based on the requirements for thevarious types of traffic and/or SOM capabilities. A radio bearer may bemapped to one or more SOMs. The WTRU may be configured with, perhaps forexample for one or more, or each, radio bearer, a set of SOMs it mayuse. The WTRU may dynamically determine, perhaps for example based onradio conditions, buffer status and/or other parameters, the SOM to use.Incompatible multiplexing of LCH may be reduced and/or avoided based onusing a (e.g., a single) transport block (TB) (e.g., limited by ratio ofdata), and/or one or more, or multiple, TBs mapped to the same physicallayer (PHY). Traffic may be prioritized perhaps for example based onlatency requirements.

A wireless transmit/receive unit (WTRU) may be in communication with awireless communication network. The WTRU may comprise a memory. The WTRUmay comprise a receiver. The receiver may be configured to receive aconfiguration. The configuration may include one or more characteristicsfor one or more transmission modes (TMs) of the WTRU. The WTRU maycomprise a processor. The processor may be configured to select,dynamically, at least one TM of the one or more TMs for a transmissionof an uplink data unit. The dynamic selection may be based on one ormore data transfer requirements and/or the one or more TMcharacteristics. The processor may be configured to identify at leastone transport channel associated with the at least one TM. The processormay be configured to map the uplink data unit to the at least onetransport channel. The WTRU may comprise a transmitter. The transmittermay be configured at least to send the transmission of the uplink dataunit to one or more devices of the wireless communication network.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a system diagram of an example communications system.

FIG. 1B is a system diagram of an example wireless transmit/receive unit(WTRU) that may be used within the communications system Illustrated inFIG. 1A.

FIG. 1C is a system diagram of an example radio access network and anexample core network that may be used within the communications systemillustrated in FIG. 1A.

FIG. 1D is a system diagram of another example radio access network andan example core network that may be used within the communicationssystem illustrated in FIG. 1A.

FIG. 1E is a system diagram of another example radio access network andan example core network that may be used within the communicationssystem illustrated in FIG. 1A.

FIG. 2 illustrates an example LTE user-plane protocol stack.

FIG. 3 illustrates an example LTE medium access control (MAC)architecture.

FIG. 4 illustrates example system bandwidths.

FIG. 5 illustrates example spectrum allocation where differentsubcarriers may be at least conceptually assigned to different modes ofoperation (“SOM”).

FIG. 6 illustrates example timing relationships for time-divisionduplexing (TDD).

FIG. 7 illustrates example timing relationships for frequency divisionduplexing (FDD).

FIG. 8 illustrates example LTE-assisted and/or unassisted deployments.

FIG. 9 illustrates example functionality of the 5G Protocol Stack at ahigh level.

FIG. 10 illustrates example high level mapping between logicalchannel(s) (LCH) and SOMs.

FIG. 11 illustrates an example (e.g., single) HARQ entity per WTRUtechnique in the context of a full protocol stack, and/or in the contextof the full functions of a protocol stack.

FIG. 12 illustrates example high level mapping between LCH and SOMs.

FIG. 13 illustrates example (e.g., single) HARQ entity per SOM techniquein the context of a full protocol stack, and/or in the context of thefull functions of a protocol stack.

FIG. 14 illustrates an example high level mapping between LCH and SOMs.

FIG. 15 illustrates an example (e.g., single) HARQ entity per SOMtechnique in the context of a full protocol stack, for example in thecontext of the full functions of a protocol stack.

FIG. 16 illustrates an example of a WTRU Controller dynamically matchingdata units to TrCH that may meet the QoS requirement of the data units.

DETAILED DESCRIPTION

A detailed description of illustrative embodiments will now be describedwith reference to the various figures. Although this descriptionprovides a detailed example of possible implementations, it should benoted that the details are intended to be examples and in no way limitthe scope of the application.

FIG. 1A is a diagram of an example communications system 100 in whichone or more disclosed embodiments may be implemented. The communicationssystem 100 may be a multiple access system that provides content, suchas voice, data, video, messaging, broadcast, etc., to multiple wirelessusers. The communications system 100 may enable multiple wireless usersto access such content through the sharing of system resources,including wireless bandwidth. For example, the communications systems100 may employ one or more channel access methods, such as code divisionmultiple access (CDMA), time division multiple access (TDMA), frequencydivision multiple access (FDMA), orthogonal FDMA (OFDMA), single-carrierFDMA (SC-FDMA), and/or the like.

As shown in FIG. 1A, the communications system 100 may include wirelesstransmit/receive units (WTRUs) 102 a, 102 b, 102 c, and/or 102 d (whichgenerally or collectively may be referred to as WTRU 102), a radioaccess network (RAN) 103/104/105, a core network 106/107/109, a publicswitched telephone network (PSTN) 108, the Internet 110, and othernetworks 112, though it will be appreciated that the disclosedembodiments contemplate any number of WTRUs, base stations, networks,and/or network elements. Each of the WTRUs 102 a, 102 b, 102 c, 102 dmay be any type of device configured to operate and/or communicate in awireless environment. By way of example, the WTRUs 102 a, 102 b, 102 c,102 d may be configured to transmit and/or receive wireless signals andmay include user equipment (WTRU), a mobile station, a fixed or mobilesubscriber unit, a pager, a cellular telephone, a personal digitalassistant (PDA), a smartphone, a laptop, a netbook, a personal computer,a wireless sensor, consumer electronics, and/or the like.

The communications systems 100 may also include a base station 114 a anda base station 114 b. Each of the base stations 114 a, 114 b may be anytype of device configured to wirelessly interface with at least one ofthe WTRUs 102 a, 102 b, 102 c, 102 d to facilitate access to one or morecommunication networks, such as the core network 106/107/109, theInternet 110, and/or the networks 112. By way of example, the basestations 114 a, 114 b may be a base transceiver station (BTS), a Node-B,an eNode B, a Home Node B, a Home eNode B, a site controller, an accesspoint (AP), a wireless router, and/or the like. While the base stations114 a, 114 b are each depicted as a single element, it will beappreciated that the base stations 114 a, 114 b may include any numberof interconnected base stations and/or network elements.

The base station 114 a may be part of the RAN 103/104/105, which mayalso include other base stations and/or network elements (not shown),such as a base station controller (BSC), a radio network controller(RNC), relay nodes, etc. The base station 114 a and/or the base station114 b may be configured to transmit and/or receive wireless signalswithin a particular geographic region, which may be referred to as acell (not shown). The cell may further be divided into cell sectors. Forexample, the cell associated with the base station 114 a may be dividedinto three sectors. Thus, in one embodiment, the base station 114 a mayinclude three transceivers, e.g., one for each sector of the cell. Inanother embodiment, the base station 114 a may employ multiple-inputmultiple output (MIMO) technology and, therefore, may utilize multipletransceivers for each sector of the cell.

The base stations 114 a, 114 b may communicate with one or more of theWTRUs 102 a, 102 b, 102 c, 102 d over an air interface 115/116/117,which may be any suitable wireless communication link (e.g., radiofrequency (RF), microwave, infrared (IR), ultraviolet (UV), visiblelight, etc.). The air interface 115/116/117 may be established using anysuitable radio access technology (RAT).

More specifically, as noted above, the communications system 100 may bea multiple access system and may employ one or more channel accessschemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and/or the like. Forexample, the base station 114 a in the RAN 103/104/105 and the WTRUs 102a, 102 b, 102 c may implement a radio technology such as UniversalMobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA),which may establish the air interface 115/116/117 using wideband CDMA(WCDMA). WCDMA may include communication protocols such as High-SpeedPacket Access (HSPA) and/or Evolved HSPA (HSPA+). HSPA may includeHigh-Speed Downlink Packet Access (HSDPA) and/or High-Speed UplinkPacket Access (HSUPA).

In another embodiment, the base station 114 a and the WTRUs 102 a, 102b, 102 c may implement a radio technology such as Evolved UMTSTerrestrial Radio Access (E-UTRA), which may establish the air interface115/116/117 using Long Term Evolution (LTE) and/or LTE-Advanced (LTE-A).

In other embodiments, the base station 114 a and the WTRUs 102 a, 102 b,102 c may implement radio technologies such as IEEE 802.16 (e.g.,Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000,CDMA2000 1X, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), InterimStandard 95 (IS-95), Interim Standard 856 (IS-856), Global System forMobile communications (GSM), Enhanced Data rates for GSM Evolution(EDGE), GSM EDGE (GERAN), and/or the like.

The base station 114 b in FIG. 1A may be a wireless router, Home Node B,Home eNode B, or access point, for example, and may utilize any suitableRAT for facilitating wireless connectivity in a localized area, such asa place of business, a home, a vehicle, a campus, and/or the like. Inone embodiment, the base station 114 b and the WTRUs 102 c, 102 d mayimplement a radio technology such as IEEE 802.11 to establish a wirelesslocal area network (WLAN). In another embodiment, the base station 114 band the WTRUs 102 c, 102 d may implement a radio technology such as IEEE802.15 to establish a wireless personal area network (WPAN). In yetanother embodiment, the base station 114 b and the WTRUs 102 c, 102 dmay utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE,LTE-A, etc.) to establish a picocell or femtocell. As shown in FIG. 1A,the base station 114 b may have a direct connection to the Internet 110.Thus, the base station 114 b may not be used to access the Internet 110via the core network 106/107/109.

The RAN 103/104/105 may be in communication with the core network106/107/109, which may be any type of network configured to providevoice, data, applications, and/or voice over internet protocol (VoIP)services to one or more of the WTRUs 102 a, 102 b, 102 c, 102 d. Forexample, the core network 106/107/109 may provide call control, billingservices, mobile location-based services, pre-paid calling, Internetconnectivity, video distribution, etc., and/or perform high-levelsecurity functions, such as user authentication. Although not shown inFIG. 1A, it will be appreciated that the RAN 103/104/105 and/or the corenetwork 106/107/109 may be in direct or indirect communication withother RANs that employ the same RAT as the RAN 103/104/105 or adifferent RAT. For example, in addition to being connected to the RAN103/104/105, which may be utilizing an E-UTRA radio technology, the corenetwork 106/107/109 may also be in communication with another RAN (notshown) employing a GSM radio technology.

The core network 106/107/109 may also serve as a gateway for the WTRUs102 a, 102 b, 102 c, 102 d to access the PSTN 108, the Internet 110,and/or other networks 112. The PSTN 108 may include circuit-switchedtelephone networks that provide plain old telephone service (POTS). TheInternet 110 may include a global system of interconnected computernetworks and devices that use common communication protocols, such asthe transmission control protocol (TCP), user datagram protocol (UDP)and the internet protocol (IP) in the TCP/IP internet protocol suite.The networks 112 may include wired or wireless communications networksowned and/or operated by other service providers. For example, thenetworks 112 may include another core network connected to one or moreRANs, which may employ the same RAT as the RAN 103/104/105 or adifferent RAT.

One or more of the WTRUs 102 a, 102 b, 102 c, 102 d in thecommunications system 100 may include multi-mode capabilities, e.g., theWTRUs 102 a, 102 b, 102 c, 102 d may include multiple transceivers forcommunicating with different wireless networks over different wirelesslinks. For example, the WTRU 102 c shown in FIG. 1 a may be configuredto communicate with the base station 114 a, which may employ acellular-based radio technology, and with the base station 114 b, whichmay employ an IEEE 802 radio technology.

FIG. 1B is a system diagram of an example WTRU 102. As shown in FIG. 1B,the WTRU 102 may include a processor 118, a transceiver 120, atransmit/receive element 122, a speaker/microphone 124, a keypad 126, adisplay/touchpad 128, non-removable memory 130, removable memory 132, apower source 134, a global positioning system (GPS) chipset 136, andother peripherals 138. It will be appreciated that the WTRU 102 mayinclude any subcombination of the foregoing elements while remainingconsistent with an embodiment. Also, embodiments contemplate that thebase stations 114 a and 114 b, and/or the nodes that base stations 114 aand 114 b may represent, such as but not limited to transceiver station(BTS), a Node-B, a site controller, an access point (AP), a home node-B,an evolved home node-B (eNodeB), a home evolved node-B (HeNB), a homeevolved node-B gateway, and proxy nodes, among others, may include oneor more of the elements depicted in FIG. 1B and described herein.

The processor 118 may be a general purpose processor, a special purposeprocessor, a conventional processor, a digital signal processor (DSP), aplurality of microprocessors, one or more microprocessors in associationwith a DSP core, a controller, a microcontroller, Application SpecificIntegrated Circuits (ASICs), Field Programmable Gate Array (FPGAs)circuits, any other type of integrated circuit (IC), a state machine,and/or the like. The processor 118 may perform signal coding, dataprocessing, power control, input/output processing, and/or any otherfunctionality that enables the WTRU 102 to operate in a wirelessenvironment. The processor 118 may be coupled to the transceiver 120,which may be coupled to the transmit/receive element 122. While FIG. 1Bdepicts the processor 118 and the transceiver 120 as separatecomponents, it will be appreciated that the processor 118 and thetransceiver 120 may be integrated together in an electronic package orchip.

The transmit/receive element 122 may be configured to transmit signalsto, or receive signals from, a base station (e.g., the base station 114a) over the air interface 115/116/117. For example, in one embodiment,the transmit/receive element 122 may be an antenna configured totransmit and/or receive radio frequency (RF) signals. In anotherembodiment, the transmit/receive element 122 may be an emitter/detectorconfigured to transmit and/or receive IR, UV, or visible light signals,for example. In yet another embodiment, the transmit/receive element 122may be configured to transmit and receive both RF and light signals. Itwill be appreciated that the transmit/receive element 122 may beconfigured to transmit and/or receive any combination of wirelesssignals.

In addition, although the transmit/receive element 122 is depicted inFIG. 1B as a single element, the WTRU 102 may include any number oftransmit/receive elements 122. More specifically, the WTRU 102 mayemploy MIMO technology. Thus, in one embodiment, the WTRU 102 mayinclude two or more transmit/receive elements 122 (e.g., multipleantennas) for transmitting and receiving wireless signals over the airinterface 115/116/117.

The transceiver 120 may be configured to modulate the signals that areto be transmitted by the transmit/receive element 122 and to demodulatethe signals that are received by the transmit/receive element 122. Asnoted above, the WTRU 102 may have multi-mode capabilities. Thus, thetransceiver 120 may include multiple transceivers for enabling the WTRU102 to communicate via multiple RATs, such as UTRA and IEEE 802.11, forexample.

The processor 118 of the WTRU 102 may be coupled to, and may receiveuser input data from, the speaker/microphone 124, the keypad 126, and/orthe display/touchpad 128 (e.g., a liquid crystal display (LCD) displayunit or organic light-emitting diode (OLED) display unit). The processor118 may also output user data to the speaker/microphone 124, the keypad126, and/or the display/touchpad 128. In addition, the processor 118 mayaccess information from, and store data in, any type of suitable memory,such as the non-removable memory 130 and/or the removable memory 132.The non-removable memory 130 may include random-access memory (RAM),read-only memory (ROM), a hard disk, or any other type of memory storagedevice. The removable memory 132 may include a subscriber identitymodule (SIM) card, a memory stick, a secure digital (SD) memory card,and/or the like. In other embodiments, the processor 118 may accessinformation from, and store data in, memory that is not physicallylocated on the WTRU 102, such as on a server or a home computer (notshown).

The processor 118 may receive power from the power source 134, and maybe configured to distribute and/or control the power to the othercomponents in the WTRU 102. The power source 134 may be any suitabledevice for powering the WTRU 102. For example, the power source 134 mayinclude one or more dry cell batteries (e.g., nickel-cadmium (NiCd),nickel-zinc (NiZn), nickel metal hydride (NiMH), lithium-ion (Li-ion),etc.), solar cells, fuel cells, and/or the like.

The processor 118 may also be coupled to the GPS chipset 136, which maybe configured to provide location information (e.g., longitude andlatitude) regarding the current location of the WTRU 102. In additionto, or in lieu of, the information from the GPS chipset 136, the WTRU102 may receive location information over the air interface 115/116/117from a base station (e.g., base stations 114 a, 114 b) and/or determineits location based on the timing of the signals being received from twoor more nearby base stations. It will be appreciated that the WTRU 102may acquire location information by way of any suitablelocation-determination method while remaining consistent with anembodiment.

The processor 118 may further be coupled to other peripherals 138, whichmay include one or more software and/or hardware modules that provideadditional features, functionality and/or wired or wirelessconnectivity. For example, the peripherals 138 may include anaccelerometer, an e-compass, a satellite transceiver, a digital camera(for photographs or video), a universal serial bus (USB) port, avibration device, a television transceiver, a hands free headset, aBluetooth® module, a frequency modulated (FM) radio unit, a digitalmusic player, a media player, a video game player module, an Internetbrowser, and/or the like.

FIG. 1C is a system diagram of the RAN 103 and the core network 106according to an embodiment. As noted above, the RAN 103 may employ aUTRA radio technology to communicate with the WTRUs 102 a, 102 b, 102 cover the air interface 115. The RAN 103 may also be in communicationwith the core network 106. As shown in FIG. 1C, the RAN 103 may includeNode-Bs 140 a, 140 b, 140 c, which may each include one or moretransceivers for communicating with the WTRUs 102 a, 102 b, 102 c overthe air interface 115. The Node-Bs 140 a, 140 b, 140 c may each beassociated with a particular cell (not shown) within the RAN 103. TheRAN 103 may also include RNCs 142 a, 142 b. It will be appreciated thatthe RAN 103 may include any number of Node-Bs and RNCs while remainingconsistent with an embodiment.

As shown in FIG. 1C, the Node-Bs 140 a, 140 b may be in communicationwith the RNC 142 a. Additionally, the Node-B 140 c may be incommunication with the RNC142b. The Node-Bs 140 a, 140 b, 140 c maycommunicate with the respective RNCs 142 a, 142 b via an Iub interface.The RNCs 142 a, 142 b may be in communication with one another via anIur interface. Each of the RNCs 142 a, 142 b may be configured tocontrol the respective Node-Bs 140 a, 140 b, 140 c to which it isconnected. In addition, each of the RNCs 142 a, 142 b may be configuredto carry out or support other functionality, such as outer loop powercontrol, load control, admission control, packet scheduling, handovercontrol, macro-diversity, security functions, data encryption, and/orthe like.

The core network 106 shown in FIG. 1C may include a media gateway (MGW)144, a mobile switching center (MSC) 146, a serving general packet radioservice (GPRS) support node (SGSN) 148, and/or a gateway GPRS supportnode (GGSN) 150. While each of the foregoing elements are depicted aspart of the core network 106, it will be appreciated that any one ofthese elements may be owned and/or operated by an entity other than thecore network operator.

The RNC 142 a in the RAN 103 may be connected to the MSC 146 in the corenetwork 106 via an IuCS interface. The MSC 146 may be connected to theMGW 144. The MSC 146 and the MGW 144 may provide the WTRUs 102 a, 102 b,102 c with access to circuit-switched networks, such as the PSTN 108, tofacilitate communications between the WTRUs 102 a, 102 b, 102 c andland-line communications devices.

The RNC 142 a in the RAN 103 may also be connected to the SGSN 148 inthe core network 106 via an IuPS interface. The SGSN 148 may beconnected to the GGSN 150. The SGSN 148 and the GGSN 150 may provide theWTRUs 102 a, 102 b, 102 c with access to packet-switched networks, suchas the Internet 110, to facilitate communications between and the WTRUs102 a, 102 b, 102 c and IP-enabled devices.

As noted above, the core network 106 may also be connected to thenetworks 112, which may include other wired or wireless networks thatare owned and/or operated by other service providers.

FIG. 1D is a system diagram of the RAN 104 and the core network 107according to an embodiment. As noted above, the RAN 104 may employ anE-UTRA radio technology to communicate with the WTRUs 102 a, 102 b, 102c over the air interface 116. The RAN 104 may also be in communicationwith the core network 107.

The RAN 104 may include eNode-Bs 160 a, 160 b, 160 c, though it will beappreciated that the RAN 104 may include any number of eNode-Bs whileremaining consistent with an embodiment. The eNode-Bs 160 a, 160 b, 160c may each include one or more transceivers for communicating with theWTRUs 102 a, 102 b, 102 c over the air interface 116. In one embodiment,the eNode-Bs 160 a, 160 b, 160 c may implement MIMO technology. Thus,the eNode-B 160 a, for example, may use multiple antennas to transmitwireless signals to, and receive wireless signals from, the WTRU 102 a.

Each of the eNode-Bs 160 a, 160 b, 160 c may be associated with aparticular cell (not shown) and may be configured to handle radioresource management decisions, handover decisions, scheduling of usersin the uplink and/or downlink, and/or the like. As shown in FIG. 1D, theeNode-Bs 160 a, 160 b, 160 c may communicate with one another over an X2interface.

The core network 107 shown in FIG. 1D may include a mobility managementgateway (MME) 162, a serving gateway 164, and a packet data network(PDN) gateway 166. While each of the foregoing elements are depicted aspart of the core network 107, it will be appreciated that any one ofthese elements may be owned and/or operated by an entity other than thecore network operator.

The MME 162 may be connected to each of the eNode-Bs 160 a, 160 b, 160 cin the RAN 104 via an S1 interface and may serve as a control node. Forexample, the MME 162 may be responsible for authenticating users of theWTRUs 102 a, 102 b, 102 c, bearer activation/deactivation, selecting aparticular serving gateway during an initial attach of the WTRUs 102 a,102 b, 102 c, and/or the like. The MME 162 may also provide a controlplane function for switching between the RAN 104 and other RANs (notshown) that employ other radio technologies, such as GSM or WCDMA.

The serving gateway 164 may be connected to each of the eNode-Bs 160 a,160 b, 160 c in the RAN 104 via the S1 interface. The serving gateway164 may generally route and forward user data packets to/from the WTRUs102 a, 102 b, 102 c. The serving gateway 164 may also perform otherfunctions, such as anchoring user planes during inter-eNode B handovers,triggering paging when downlink data is available for the WTRUs 102 a,102 b, 102 c, managing and storing contexts of the WTRUs 102 a, 102 b,102 c, and/or the like.

The serving gateway 164 may also be connected to the PDN gateway 166,which may provide the WTRUs 102 a, 102 b, 102 c with access topacket-switched networks, such as the Internet 110, to facilitatecommunications between the WTRUs 102 a, 102 b, 102 c and IP-enableddevices.

The core network 107 may facilitate communications with other networks.For example, the core network 107 may provide the WTRUs 102 a, 102 b,102 c with access to circuit-switched networks, such as the PSTN 108, tofacilitate communications between the WTRUs 102 a, 102 b, 102 c andland-line communications devices. For example, the core network 107 mayinclude, or may communicate with, an IP gateway (e.g., an IP multimediasubsystem (IMS) server) that serves as an interface between the corenetwork 107 and the PSTN 108. In addition, the core network 107 mayprovide the WTRUs 102 a, 102 b, 102 c with access to the networks 112,which may include other wired or wireless networks that are owned and/oroperated by other service providers.

FIG. 1E is a system diagram of the RAN 105 and the core network 109according to an embodiment. The RAN 105 may be an access service network(ASN) that employs IEEE 802.16 radio technology to communicate with theWTRUs 102 a, 102 b, 102 c over the air interface 117. As will be furtherdiscussed below, the communication links between the differentfunctional entities of the WTRUs 102 a, 102 b, 102 c, the RAN 105, andthe core network 109 may be defined as reference points.

As shown in FIG. 1E, the RAN 105 may include base stations 180 a, 180 b,180 c, and an ASN gateway 182, though it will be appreciated that theRAN 105 may include any number of base stations and ASN gateways whileremaining consistent with an embodiment. The base stations 180 a, 180 b,180 c may each be associated with a particular cell (not shown) in theRAN 105 and may each include one or more transceivers for communicatingwith the WTRUs 102 a, 102 b, 102 c over the air interface 117. In oneembodiment, the base stations 180 a, 180 b, 180 c may implement MIMOtechnology. Thus, the base station 180 a, for example, may use multipleantennas to transmit wireless signals to, and receive wireless signalsfrom, the WTRU 102 a. The base stations 180 a, 180 b, 180 c may alsoprovide mobility management functions, such as handoff triggering,tunnel establishment, radio resource management, traffic classification,quality of service (QoS) policy enforcement, and/or the like. The ASNgateway 182 may serve as a traffic aggregation point and may beresponsible for paging, caching of subscriber profiles, routing to thecore network 109, and/or the like.

The air interface 117 between the WTRUs 102 a, 102 b, 102 c and the RAN105 may be defined as an R1 reference point that implements the IEEE802.16 specification. In addition, each of the WTRUs 102 a, 102 b, 102 cmay establish a logical interface (not shown) with the core network 109.The logical interface between the WTRUs 102 a, 102 b, 102 c and the corenetwork 109 may be defined as an R2 reference point, which may be usedfor authentication, authorization, IP host configuration management,and/or mobility management.

The communication link between each of the base stations 180 a, 180 b,180 c may be defined as an R8 reference point that includes protocolsfor facilitating WTRU handovers and the transfer of data between basestations. The communication link between the base stations 180 a, 180 b,180 c and the ASN gateway 182 may be defined as an R6 reference point.The R6 reference point may include protocols for facilitating mobilitymanagement based on mobility events associated with each of the WTRUs102 a, 102 b, 102 c.

As shown in FIG. 1E, the RAN 105 may be connected to the core network109. The communication link between the RAN 105 and the core network 109may defined as an R3 reference point that includes protocols forfacilitating data transfer and mobility management capabilities, forexample. The core network 109 may include a mobile IP home agent(MIP-HA) 184, an authentication, authorization, accounting (AAA) server186, and a gateway 188. While each of the foregoing elements aredepicted as part of the core network 109, it will be appreciated thatany one of these elements may be owned and/or operated by an entityother than the core network operator.

The MIP-HA may be responsible for IP address management, and may enablethe WTRUs 102 a, 102 b, 102 c to roam between different ASNs and/ordifferent core networks. The MIP-HA 184 may provide the WTRUs 102 a, 102b, 102 c with access to packet-switched networks, such as the Internet110, to facilitate communications between the WTRUs 102 a, 102 b, 102 cand IP-enabled devices. The AAA server 186 may be responsible for userauthentication and for supporting user services. The gateway 188 mayfacilitate interworking with other networks. For example, the gateway188 may provide the WTRUs 102 a, 102 b, 102 c with access tocircuit-switched networks, such as the PSTN 108, to facilitatecommunications between the WTRUs 102 a, 102 b, 102 c and land-linecommunications devices. In addition, the gateway 188 may provide theWTRUs 102 a, 102 b, 102 c with access to the networks 112, which mayinclude other wired or wireless networks that are owned and/or operatedby other service providers.

Although not shown in FIG. 1E, it will be appreciated that the RAN 105may be connected to other ASNs and the core network 109 may be connectedto other core networks. The communication link between the RAN 105 theother ASNs may be defined as an R4 reference point, which may includeprotocols for coordinating the mobility of the WTRUs 102 a, 102 b, 102 cbetween the RAN 105 and the other ASNs. The communication link betweenthe core network 109 and the other core networks may be defined as an R5reference, which may include protocols for facilitating interworkingbetween home core networks and visited core networks.

In view of FIGS. 1A-1E, and the corresponding description of FIGS.1A-1E, one or more, or all, of the functions described herein withregard to one or more of: WTRU 102 a-d, Base Station 114 a-b, Node B 140a-c, RNC 142 a-b, MSC 146, SGSN 148, MGW 144, CGSN 150, eNode-B 160 a-c,MME 162, Serving Gateway 164, PDN Gateway 166, Base Station 180 a-c, ASNGateway 182, AAA 186, MIP-HA 184, and/or Gateway 188, or the like, maybe performed by one or more emulation devices (not shown) (e.g., one ormore devices configured to emulate one or more, or all, of the functionsdescribed herein).

The one or more emulation devices may be configured to perform the oneor more, or all, functions in one or more modalities. For example, theone or more emulation devices may perform the one or more, or all,functions while being fully or partially implemented/deployed as part ofa wired and/or wireless communication network. The one or more emulationdevices may perform the one or more, or all, functions while beingtemporarily implemented/deployed as part of a wired and/or wirelesscommunication network. The one or more emulation devices may perform theone or more, or all, functions while not being implemented/deployed aspart of a wired and/or wireless communication network (e.g., such as ina testing scenario in a testing laboratory and/or a non-deployed (e.g.testing) wired and/or wireless communication network, and/or testingperformed on one or more deployed components of a wired and/or wirelesscommunication network). The one or more emulation devices may be testequipment.

By way of example, and not limitation, one or more of the followingacronyms may be referenced herein:

Δf Sub-carrier spacing 5gFlex 5G Flexible Radio Access Technology 5gNB5GFlex NodeB ACK Acknowledgement BLER Block Error Rate BTI Basic TI (ininteger multiple of one or more symbol duration) CB Contention-Based(e.g., access, channel, resource) CoMP Coordinated Multi-Pointtransmission/reception CP Cyclic Prefix CP-OFDM Conventional OFDM(relying on cyclic prefix) CQI Channel Quality Indicator CN Core Network(e.g., LTE packet core) CRC Cyclic Redundancy Check CSI Channel StateInformation CSG Closed Subscriber Group DC Dual Connectivity D2D Deviceto Device transmissions (e.g., LTE Sidelink) DCI Downlink ControlInformation DL Downlink DM-RS Demodulation Reference Signal DRB DataRadio Bearer EPC Evolved Packet Core FBMC Filtered Band Multi-Carrier

By way of example, and not limitation, one or more of the followingacronyms may be referenced herein:

FBMC/OQAM A FBMC technique using Offset Quadrature Amplitude ModulationFDD Frequency Division Duplexing FDM Frequency Division MultiplexingHARQ Hybrid Automatic Repeat Request (ARQ) ICC Industrial Control andCommunications ICIC Inter-Cell Interference Cancellation IP InternetProtocol LAA License Assisted Access LBT Listen-Before-Talk LCH LogicalChannel LCP Logical Channel Prioritization LLC Low LatencyCommunications LTE Long Term Evolution e.g., from 3GPP LTE R8 and up MACMedium Access Control NACK Negative ACK MBB Massive BroadbandCommunications MC MultiCarrier MCS Modulation and Coding Scheme MIMOMultiple Input Multiple Output MTC Machine-Type Communications NASNon-Access Stratum OFDM Orthogonal Frequency-Division Multiplexing

By way of example, and not limitation, one or more of the followingacronyms may be referenced herein:

OOB Out-Of-Band (emissions) P_(cmax) Total available WTRU power in agiven TI PHY Physical Layer PRACH Physical Random Access Channel PDUProtocol Data Unit PER Packet Error Rate PL Path Loss (Estimation) PLMNPublic Land Mobile Network PLR Packet Loss Rate PSS PrimarySynchronization Signal QoS Quality of Service (from the physical layerperspective) QCI QoS Class Identifier RAB Radio Access Bearer RACHRandom Access Channel (or procedure) RF Radio Front end RNTI RadioNetwork Identifier RRC Radio Resource Control RRM Radio ResourceManagement RS Reference Signal RTT Round-Trip Time

By way of example, and not limitation, one or more of the followingacronyms may be referenced herein:

SCMA Single Carrier Multiple Access SDU Service Data Unit SOM SpectrumOperation Mode SS Synchronization Signal SSS Secondary SynchronizationSignal SRB Signalling Radio Bearer SWG Switching Gap (in aself-contained subframe) TB Transport Block TBS Transport Block Size TDDTime-Division Duplexing TDM Time-Division Multiplexing TI Time Interval(in integer multiple of one or more BTI) TTI Transmission Time Interval(in integer multiple of one or more TI) TrCH Transport Channel TRPTransmission / Reception Point TRx Transceiver UCI Uplink ControlInformation (e.g., HARQ feedback, CSI) UFMC Universal FilteredMultiCarrier UF-OFDM Universal Filtered OFDM UL Uplink URCUltra-Reliable Communications URLLC Ultra-Reliable and Low LatencyCommunications V2V Vehicle to vehicle communications V2X Vehicularcommunications WLAN domain). Wireless Local Area Networks and relatedtechnologies (IEEE 802.xx

FIG. 2 illustrates an example LTE user-plane protocol stack. The radioprotocol architecture for the LTE user plane shown in FIG. 2 may includethe PDCP, RLC MAC and/or physical layer (PHY) sublayers. One or more, oreach, sublayer may be responsible for a subset of functions used totransfer data from the WTRU to the eNB (and for example, vice-versa)over the radio medium.

The MAC sublayer may offer a number of services and/or functionsincluding, but not limited to: multiplexing/demultiplexing of MACservice data units (SDUs) belonging to one or more, or different,logical channels into/from transport blocks (TB) delivered to/from thephysical layer on transport channels; scheduling information reporting;error correction through HARQ; priority handling between logicalchannels of at least one WTRU; priority handling between WTRUs by meansof dynamic scheduling; MBMS service identification; transport formatselection; and/or padding.

FIG. 3 illustrates an example LTE MAC architecture. As shown, thevarious functions may interact with each other. Logical channelprioritization (specified for the uplink) and/or multiplexing arefunctions that may be used to determine and/or select the set of data totransmit in a specific TTI (MAC protocol data unit (PDU)).

The Hybrid-ARQ (HARQ) functionality may control the fast retransmissionsover the air. HARQ may rely on fast acknowledgement/negativeacknowledgement (ACK/NACK) feedback provided by the physical layer inorder to determine whether a retransmission may be useful, or not.Because of the inherent delay in LTE associated to providing thefeedback (e.g., the receiver may decode and/or transmit the feedback),one or more, or multiple, concurrent HARQ processes may be used (e.g.,up to 8 in LTE). One or more, or each, HARQ process may carry adifferent MAC PDU and/or may operate independently with respect totransmissions and/or retransmissions.

HARQ retransmissions on the LTE uplink may be synchronous. For example,there may be a fixed time relationship between transmissions andretransmissions of a given MAC PDU. On the LTE downlink HARQ operationsmay be asynchronous, and/or the HARQ process ID may be explicitlysignaled on the downlink signaling grant. HARQ Ack/Nack may be sent bythe WTRU with a fixed timing with respect to the associated transmission(e.g., 4 TTI after).

A 5G flexible air interface may be provided to enable improved broadbandperformance (IBB), industrial control and communications (ICC),vehicular applications (V2X) and/or massive machine-type communications(mMTC). The 5G flexible air interface may provide support for ultra-lowtransmission latency (LLC). Air interface latency may be as low as 1 msround-trip time (RTT) and/or may provide support for TTIs somewherebetween 100us and (perhaps for example, no larger than) 250us. The 5Gflexible air interface may provide support for ultra-low access latency(e.g., time from initial system access until the completion of thetransmission of the first user plane data unit) is of interest but oflesser priority. The 5G flexible air interface may provide support forend-to-end (e2e) latency of less than 10 ms. The 5G flexible airinterface may provide support for ultra-reliable transmission (URC).Target may be 99.999% transmission success and/or service availability.

The 5G flexible air interface may provide support for mobility for speedin the range of 0-500 km/h. At least IC and/or V2X may have packet lossratio of less than 10e-6. Support for machine-type communications (MTC)operation (including narrowband operation) may be provided. The airinterface may support narrowband operation (e.g., using less than 200KHz), extended battery life (e.g., up to 15 years of autonomy) and/orminimal communication overhead for small and/or infrequent datatransmissions e.g., low data rate in the range of 1-100kbps with accesslatency of seconds to hours.

A flexible radio access system may be provided. OFDM is used as thebasic signal format for data transmissions in LTE and/or in IEEE 802.11.OFDM may divide the spectrum into one or more, or multiple, parallelorthogonal subbands. One or more, or each, subcarrier is shaped using arectangular window in the time domain leading to sinc-shaped subcarriersin the frequency domain. OFDMA may be associated with perfect frequencysynchronization and/or tight management of uplink timing alignmentwithin the duration of the cyclic prefix to maintain orthogonalitybetween signals and/or to minimize intercarrier interference. Such tightsynchronization might not be well-suited in a system where a WTRU isconnected to multiple access points (e.g., simultaneously). Powerreduction may be applied to uplink transmissions to compliant withspectral emission requirements to adjacent bands, in particular in thepresence of aggregation of fragmented spectrum for the WTRU’stransmissions.

Some of the shortcomings of conventional OFDM (CP-OFDM) can be addressedby more stringent RF requirements for implementations, and/or whenoperating using large amount of contiguous spectrum not requiringaggregation. A CP-based OFDM transmission scheme may lead to a downlinkphysical layer for 5G similar to that of legacy system e.g., mainlymodifications to pilot signal density and/or location.

A number of principles applicable to the design of a flexible radioaccess for 5G are described herein. The descriptions herein are notmeant to limit in any way the applicability of the methods describedfurther herein to other wireless technologies and/or to wirelesstechnology using different principles, when applicable.

The 5G Flexible Radio Access Technology (5gFLEX) downlink transmissionscheme may be based on a multicarrier waveform characterized by highspectral containment (e.g., lower side lobes and/or lower Out-Of-Band(OOB) emissions). Multi-carrier (MC) waveform candidates for 5G mayinclude, but not limited to, OFDM-OQAM (offset quadrature amplitudemodulation) and/or universal filtered MultiCarrier (UFMC) (UF-OFDM).

Multicarrier modulation waveforms may divide the channel intosubchannels and/or modulate data symbols on subcarriers in thesesubchannels. With OFDM-OQAM, a filter may be applied in the time domainper subcarrier to the OFDM signal to reduce OOB.

With UFMC (UF-OFDM), a filter may be applied in the time domain to theOFDM signal to reduce OOB. Filtering may be applied per subband to usespectrum fragments thereby reducing complexity and/or making UF-OFDMsomewhat more practical to implement.

Methods described herein are however not limited to the waveformsdescribed herein and/or may be applicable to other waveforms. Thewaveforms described herein will be further used for exemplary purposes.

Such waveforms may enable multiplexing in frequency of signals withnon-orthogonal characteristics (e.g., such as different subcarrierspacing) and/or co-existence of asynchronous signals without requiringcomplex interference cancellation receivers. It may facilitate theaggregation of fragmented pieces of spectrum in the baseband processingas a lower cost alternative to its implementation as part of the RFprocessing.

Different waveforms may coexist within the same band. The mMTCnarrowband operation may be supported, for example, using single carriermultiple access (SCMA). The combination of different waveforms e.g.,CP-OFDM, OFDM-OQAM and/or UF-OFDM within the same band may be supportedfor all aspects and/or for downlink and/or uplink transmissions. Suchco-existence may include transmissions using different types ofwaveforms between different WTRUs and/or transmissions from the sameWTRU, e.g., simultaneously, with some overlap and/or consecutive in thetime domain.

Hybrid types of waveforms may be supported. For example, waveformsand/or transmissions may support at least one of: a possibly varyingcyclic prefix (CP) duration (e.g., from one transmission to another), acombination of a CP and a low power tail (e.g., a zero tail), a form ofhybrid guard interval (e.g., using a low power CP and an adaptive lowpower tail) and/or the like. Such waveforms may support dynamicvariation and/or control of further aspects such as how to applyfiltering (e.g., whether filtering is applied at the edge of thespectrum used for reception of any transmission(s) for a given carrierfrequency, and/or at the edge of a spectrum used for reception of atransmission associated to a specific SOM, and/or per subband, and/orper group thereof).

The uplink transmissions may use a same or different waveform as fordownlink transmissions. Multiplexing of transmissions to and fromdifferent WTRUs in the same cell may be based on FDMA and/or TDMA.

The 5gFLEX radio access system may be characterized by a very highdegree of spectrum flexibility that enables deployment in differentfrequency bands with different characteristics, including differentduplex arrangements, different and/or variable sizes of the availablespectrum including contiguous and/or non-contiguous spectrum allocationsin the same or different bands. It may support variable timing aspectsincluding support for one or more, or multiple, TTI lengths and/orsupport for asynchronous transmissions.

The 5gFLEX radio access system may provide flexibility in duplexingarrangement. TDD and/or FDD duplexing schemes can be supported. For FDDoperation, supplemental downlink operation may be supported usingspectrum aggregation. FDD operation may support full-duplex FDD and/orhalf-duplex FDD operation. For TDD operation, the downlink (DL)/uplink(UL) allocation may be dynamic. DL/UL allocation might not be based on afixed DL/UL frame configuration. The length of a DL and/or a ULtransmission interval may be set per transmission opportunity.

The 5gFLEX radio access system may provide bandwidth flexibility, e.g.,to enable the possibility for different transmission bandwidths onuplink and/or downlink ranging from anything between a nominal systembandwidth up to a maximum value corresponding to the system bandwidth.

For single carrier operation, supported system bandwidths may, forexample, include 5, 10, 20, 40, and/or 80 MHz and/or the like. Possibly,supported system bandwidths could be any bandwidth in a given rangee.g., from a few MHz up to 160 MHz. Nominal bandwidths could possiblyhave one or more fixed possible values. Narrowband transmissions of upto 200 KHz could be supported within the operating bandwidth for MTCdevices.

System bandwidth, as used herein, may include the largest portion ofspectrum that can be managed by the network for a given carrier. Forsuch a carrier, the portion that a WTRU minimally supports for cellacquisition, measurements and/or initial access to the network maycorrespond to the nominal system bandwidth. The WTRU may be configuredwith a channel bandwidth that is within the range of the entire systembandwidth. FIG. 4 illustrates example system bandwidths. The WTRU’sconfigured channel bandwidth may or might not include the nominal partof the system bandwidth as shown FIG. 4 .

Bandwidth flexibility can be achieved because the applicable set of RFrequirements for a given maximum operating bandwidth in a band can bemet without the introduction of additional allowed channel bandwidthsfor that operating band due to the efficient support of basebandfiltering of the frequency domain waveform.

Methods to configure, reconfigure and/or dynamically change the WTRU’schannel bandwidth for single carrier operation are contemplated, as wellas methods to allocate spectrum for narrowband transmissions within thenominal system, system and/or configured channel bandwidth.

The physical layer of a 5G air interface may be band-agnostic and/or maysupport operation in licensed bands below 5 GHz as well as operation inthe unlicensed bands in the range 5-6 GHz. For operation in theunlicensed bands, listen-before-talk (LBT) Cat 4 based channel accessframework similar to LTE license assisted access (LAA) may be supported.

Methods to scale and/or manage (e.g., scheduling, addressing ofresources, broadcasted signals, measurements) cell-specific and/orWTRU-specific channel bandwidths for arbitrary spectrum block sizes arecontemplated.

The 5gFLEX radio access system may provide flexible spectrum allocation.Downlink control channels and/or signals support FDM operation. A WTRUcan acquire a downlink carrier by receiving transmissions using thenominal part of the system bandwidth. For example, the WTRU might notinitially be required to receive transmissions covering the entirebandwidth that is being managed by the network for the concernedcarrier.

Downlink data channels can be allocated over a bandwidth that may ormight not correspond to the nominal system bandwidth, withoutrestrictions other than being within the WTRU’s configured channelbandwidth. For example, the network may operate a carrier with a 12 MHzsystem bandwidth using a 5 MHz nominal bandwidth allowing devicessupporting at most 5 MHz maximum RF bandwidth to acquire and/or accessthe system while possibly allocating +10 to -10 MHz of the carrierfrequency to other WTRU’s supporting up to 20 MHz worth of channelbandwidth.

FIG. 5 illustrates example spectrum allocation where differentsubcarriers may be at least conceptually assigned to different modes ofoperation (Spectrum Operating Modes (SOMs). Different SOMs can be usedto fulfill different requirements for different transmissions. A SOM mayinclude at least one of a subcarrier spacing, a TTI length, and one ormore reliability aspects e.g., HARQ processing aspects, and/or asecondary control channel. A SOM may include a specific waveform and/ormay include a processing aspect e.g., in support of co-existence ofdifferent waveforms in the same carrier using FDM and/or TDM.Coexistence of FDD operation in a TDD band may be supported e.g., in aTDM manner and/or similar.

The WTRU may be configured to perform transmissions according to one ormore SOMs. For example, a SOM may correspond to transmissions that mayuse at least one of the following: a specific TTI duration, a specificinitial power level, a specific HARQ processing type, a specific upperbound for successful HARQ reception/transmission, a specificconfiguration of set(s) of resources (e.g., network managed) for WTRUoperation, a specific physical channel (uplink and/or downlink), aspecific operating frequency, band and/or carrier, and/or a specificwaveform type and/or a transmission according to a specific RAT (e.g.,legacy LTE and/or according to a 5G transmission method). A SOM maycorrespond to one or more of: a QoS level and/or related aspect e.g.,maximum/target latency, maximum/target block error rate (BLER), and/orthe like.

A SOM may correspond to a spectrum area and/or to a specific controlchannel and/or aspect thereof (e.g., including search space, and/ordownlink control information (DCI) type, etc.). For example, a WTRU maybe configured with a SOM for one or more, or each, of a URC type ofservice, a LLC type of service, and/or a MBB type of service. A WTRU mayhave a configuration for a SOM for system access and/or fortransmission/reception of L3 control signaling (e.g., radio resourcecontrol (RRC) signaling), e.g., in a portion of a spectrum associated tothe system such as in a nominal system bandwidth as described herein.

As described herein, a SOM may be a characterization of a block ofphysical resources in time, space, and/or frequency. A SOM may includeapplicable set(s) of operations. A Transmission Mode (TM) may correspondto an instance (e.g., a specific instance) of a SOM characterization,perhaps for example in terms of a specific configuration. For example, aspecific configuration may include one or more of: an applicable TTIduration, set of physical resource blocks, type of waveform, etc.). ATransmission Mode (TM) may also correspond to control signaling. Forexample, a TM may be referred to by downlink control signaling on acontrol channel. A transmission mode (TM) may correspond to aconfiguration of the WTRU such that the WTRU may determine one or moreparameters applicable for the processing of the transmission (UL or DL),perhaps for example when the WTRU receives an assignment of one or moreresources. A configuration of a TM (e.g., an applicable TM) may indicateto the WTRU how to receive WTRU-specific reference signals, how tointerpret downlink control signaling received on PDCCH, and/or how tointerpret precoding bits, and the like.

For single carrier operation, spectrum aggregation may be supportedwhereby the WTRU may support transmission and/or reception of one ormore, or multiple, transport blocks over contiguous and/ornon-contiguous sets physical resource blocks (PRBs) within the sameoperating band. A (e.g., a single) transport block may be mapped toseparate sets of PRBs. Support for simultaneous transmissions associatedto different SOM requirements may be provided.

Multicarrier operation may be supported using contiguous and/ornon-contiguous spectrum blocks within the same operating band and/oracross two or more operating bands. Aggregation of spectrum blocks usingdifferent modes, e.g., FDD and/or TDD and/or using different channelaccess methods (e.g., licensed and/or unlicensed band operation below 6GHz) may be supported. Support for methods that configure, reconfigureand/or dynamically change the WTRU’s multicarrier aggregation may beprovided.

Flexible framing, timing and/or synchronization may be supported.Downlink and/or uplink transmissions may be organized into radio framescharacterized by a number of fixed aspects (e.g., location of downlinkcontrol information) and/or a number of varying aspects (e.g.,transmission timing, supported types of transmissions).

The basic time interval (BTI) may be expressed in terms of an integernumber of one or more symbol(s), and/or symbol duration that may be afunction of the subcarrier spacing applicable to the time-frequencyresource. For FDD, subcarrier spacing may differ between the uplinkcarrier frequency f_(UL) and the downlink carrier frequency f_(DL) for agiven frame.

A transmission time interval (TTI) may be the minimum time supported bythe system between consecutive transmissions. Consecutive transmissionsmay be associated with different transport blocks (TBs) for the downlink(TTI_(DL)), for the uplink transceiver (UL TRx) perhaps for exampleexcluding any preamble (e.g., if applicable) and/or perhaps includingany control information (e.g., DCI for downlink and/or uplink controlinformation (UCI) for uplink). A TTI may be expressed in terms ofinteger number of one of more BTI(s). A BTI may be specific and/orassociated with a given SOM.

Supported frame duration may include, but not limited to, 100us, 125us(⅛ms), 142.85us (⅐ms is 2 nCP LTE OFDM symbols) and 1 ms to enablealignment with the legacy LTE timing structure.

A frame may start with downlink control information (DCI) of a fixedtime duration t_(dci) preceding any downlink data transmission (DL TRx)for the concerned carrier frequency - f_(UL)+DL for TDD and f_(DL) forFDD. For TDD duplexing (e.g., only TDD duplexing), a frame may include adownlink portion (DCI and/or DL TRx) and/or an uplink portion (UL TRx).A switching gap (swg) may precede the uplink portion of the frame, ifpresent.

For FDD duplexing (e.g., only FDD duplexing), a frame may include adownlink reference TTI and/or one or more TTI(s) for the uplink. Thestart of an uplink TTI may be derived using an offset (t_(offset))applied from the start of the downlink reference frame that may overlapwith the start of the uplink frame.

For TDD, 5gFLEX may support Device to Device transmissions (D2D)/Vehicular communications (V2X)/Sidelink operation in the frame byincluding respective downlink control and/or forward directiontransmission in the DCI + DL TRx portion (e.g., if a semi-staticallocation of the respective resources is used) and/or in the DL TRxportion (e.g., only such portion) (e.g., for dynamic allocation) and/orby including the respective reverse direction transmission in the UL TRxportion.

For FDD, 5gFLEX may support D2D/V2X/Sidelink operation in the UL TRxportion of the frame by including respective downlink control, forwarddirection and/or reverse direction transmissions in the UL TRx portion(e.g., dynamic allocation of the respective resources may be used).

FIG. 6 illustrates example frame structure and/or frame timingrelationships for TDD duplexing. FIG. 7 illustrates example framestructure and/or frame timing relationships for FDD duplexing.

A WTRU may receive downlink control information (DCI) from at least onedevice of one or more devices of a wireless communication network. TheWTRU may identify a resource allocation indicated by the DCI fortransmission of an uplink data unit. The WTRU may determine a Quality ofService (QoS) requirement for the transmission of the uplink data unit.The WTRU may determine if the resource allocation indicated by the DCIfor transmission of the uplink data unit at least satisfies, or fails tosatisfy, the QoS requirement. The WTRU may determine to not utilize theresource allocation indicated by the DCI for the transmission of theuplink data unit, perhaps for example when the resource allocationindicated by the DCI fails to satisfy (e.g., is determined to fail tosatisfy) the QoS requirement.

The WTRU may identify a resource allocation corresponding to the atleast one TM of the one or more TMs for the transmission of the uplinkdata unit. The WTRU may determine to utilize the resource allocationcorresponding to the at least one TM of the one or more TMs for thetransmission of the uplink data unit (e.g., in lieu of the resourceallocation indicated by the DCI for transmission of the uplink dataunit), perhaps for example when the resource allocation provided by theDCI fails to satisfy (e.g., is determined to fail to satisfy) the QoSrequirement.

A scheduling function may be supported in the MAC layer. A schedulingmode may be selected. The available scheduling modes may includenetwork-based scheduling for tight scheduling in terms of resources,timing and/or transmission parameters of downlink transmissions and/oruplink transmissions, and/or WTRU-based scheduling for more flexibilityin terms of timing and/or transmission parameters. Schedulinginformation may be valid for a single and/or for one or more, ormultiple, TTIs.

Network-based scheduling may enable the network to tightly manage theavailable radio resources assigned to different WTRUs such as tooptimize the sharing of such resources. Dynamic scheduling may besupported.

WTRU-based scheduling may enable the WTRU to opportunistically accessuplink resources with minimal latency on a per-need basis within a setof shared and/or dedicated uplink resources assigned (e.g., dynamicallyand/or not) by the network. Synchronized and/or unsynchronizedopportunistic transmissions may be supported. Contention-basedtransmissions and/or contention-free transmissions may be supported.

Logical channel prioritization may be performed based on data availablefor transmission and/or available resources for uplink transmissions.Multiplexing of data with different QoS requirements within the sametransport block may be provided.

Forward error correction (FEC) and/or block coding be performed. Atransmission may be encoded using a number of different encodingmethods. Different encoding methods may have different characteristics.For example, an encoding method may generate a sequence of informationunits. One or more, or each, information unit, and/or block, may beself-contained. For example, an error in the transmission of a firstblock might not impair the ability of the receiver to successfullydecode a second block, in particular if the second block is error-freeand/or if sufficient redundancy can be found in the second block and/orin a different block for which at least a portion was successfullydecoded.

Example of encoding methods may include raptor/fountain codes whereby atransmission may include a sequence of N raptor codes. One or more suchcodes may be mapped to one or more transmission “symbols” in time. A“symbol” may correspond to one or more set of information bits, e.g.,one or more octets. Such encoding may be used to add FEC to atransmission whereby the transmission could use N+1 and/or N+2 raptorcodes (and/or symbols, perhaps for example assuming a one raptor codesymbol relationship). This may make the transmission more resilient tothe loss of one “symbol”, for example due to interference and/orpuncturing by another transmission overlapping in time.

The WTRU may receive and/or detect one or more system signature. Asystem signature may include a signal structure using a sequence. Suchsignal may be similar to a synchronization signal e.g., similar to LTEprimary synchronization signal (PSS) and/or secondary synchronizationsignal (SSS). Such signature may be specific (e.g., uniquely identify)to a particular node (and/or transmission/reception point (TRP)) withina given area or it may be common to a plurality of such nodes (and/orTRPs) within an area. Such aspect(s) might not be known and/or relevantto the WTRU. The WTRU may determine and/or detect a system signaturesequence and/or further determine one or more parameters associated tothe system. For example, the WTRU may derive an index therefrom, and/ormay use such index to retrieve associated parameters e.g., within atable such as the access table described below. For example, the WTRUmay use the received power associated with the signature for open-looppower control e.g., for the purpose of setting the initial transmissionpower if the WTRU determines that it may access (and/or transmit to)using applicable resources of the system. For example, the WTRU may usethe timing of the received signature sequence e.g., for the purpose ofsetting the timing of a transmission (e.g., a preamble on a physicalrandom access channel (PRACH) resource) if the WTRU determines that itmay access (and/or transmit) using applicable of the system.

The WTRU may be configured with a list of one or more entries. Such alist may be referred to as an access table. Such a list may be indexed.One or more, or each, entry may be associated to a system signatureand/or to a sequence thereof. Such access table may provide initialaccess parameters for one or more areas. One or more, or each, suchentry may provide one or more parameters that may be useful forperforming an initial access to the system. Such parameters may includeat least one of a set of one or more random access parameters (e.g.,including applicable physical layer resources (e.g., PRACH resources) intime and/or frequency), initial power level, and/or physical layerresources for reception of a response. Such parameters may includeaccess restrictions, for example including public land mobile network(PLMN) identity and/or closed subscriber group (CSG) information. Suchparameters may include routing-related information such as theapplicable routing area(s). One or more, or each, such entry may beassociated with, and/or indexed by, a system signature. In other words,one such entry may possibly be common to a plurality of nodes (and/orTRPs). The WTRU may receive such access table by means of a transmissionusing dedicated resources e.g., by RRC configuration and/or by means ofa transmission using broadcasted resources. In the latter case, theperiodicity of the transmission of an access table may be relativelylong (e.g., up to 10240 ms) e.g., it may be longer than the periodicityof the transmission of a signature (e.g., in the range of 100 ms).

FIG. 8 illustrates example LTE-assisted and/or unassisted deployments.For initial deployments using a phased approach, 5G systems may bedeployed under the umbrella of an existing LTE system. In thisLTE-Assisted deployment scenario, an LTE network may provide basiccellular functions such as mobility to/from LTE, core network functionsand so on. The deployments may evolve such that the 5G systems maybecome standalone, independent of LTE, e.g., unassisted.

A protocol architecture and/or associated functions for a 5gFLEX systemmay be implemented. Although described in the context of a 5G RAT, thesolutions described may also be applicable to the evolution of otherRATs, such as LTE and/or Wi-Fi.

A stand-alone 5gFLEX radio access network may be provided. For example,the stand-alone 5gFLEX radio access network might not be assisted by anLTE network. Although solutions based on a standalone 5G deploymentarchitecture are described here, the solution provided here may also beapplicable to the LTE-Assisted architecture.

The 5G protocol stack may offer a transport service of IP packets from asource node to a destination node over a wireless medium. FIG. 9illustrates example functionality of the 5G Protocol Stack at a highlevel. The functions of the protocol stack may include one or more of,depending on the implementation and/or configuration, headercompression, security, integrity protection, ciphering, segmentation,concatenation, multiplexing, ARQ, mapping to spectrum operating mode(SOM), modulation and/or coding, HARQ, and/or mapping toantenna/physical channels.

A logical channel (LCH) may represent a logical association between datapackets and/or PDUs. LCH may have a different and/or broader meaningthan a similar term for previous generations, such as LTE systems. Forexample, a logical association may be based on data units beingassociated with the same bearer and/or being associated with the sameSOM and/or slice (e.g., a processing path using a set of physicalresources). For example, an association may be characterized by one ormore of: a chaining of processing functions, an applicable physical data(and/or control) channel (and/or instance thereof), and/or aninstantiation of a protocol stack, which may include one or more of: aportion being centralized, such as PDCP (e.g., only PDCP) and/oranything beyond portions of the physical layer processing (e.g., RadioFront (RF) end, and/or another portion being closer to the edge (e.g.,MAC/PHY in the TRP and/or RF only), which may be separated by a fronthauling interface.

A logical channel group (LCG) may include a group of LCH(s) and/orequivalent (e.g., as described above). LCG may have a different and/orbroader meaning than a similar term for previous generations, such asLTE systems. A grouping may be based on one or more criteria. Forexample, criteria may be that one or more LCH(s) have a similar prioritylevel that is applicable to (and/or associated with) one or more of: oneor more, or all, LCHs of the same LCG (similar to legacy), the same SOM(and/or type thereof), and/or the same slice (and/or type thereof). Forexample, an association may characterized by one or more of: a chainingof processing functions, an applicable physical data (and/or control)channel (and/or instance thereof), and/or an instantiation of a protocolstack, which may include a specific portion being centralized (e.g.,PDCP only and/or anything except RF) and/or another portion being closerto the edge (e.g., MAC/PHY in the TRP, and/or RF only), which may beseparated by a front-hauling interface.

A transport channel (TrCH) may include a (e.g., specific) set ofprocessing steps and/or a set of functions applied to data informationthat may affect one or more transmission characteristics over a radiointerface.

TrCH may be defined (e.g., for LTE) with one or more, or multiple, typesof TrCH, such as the Broadcast Channel (BCH), the Paging Channel (PCH),the Downlink Shared Channel (DL-SCH), the Multicast Channel (MCH), theUplink Shared Channel (UL-SCH) and/or the Random Access Channel, whichmay or might not carry user plane data. Main transport channels forcarrying user plane data may be the DL-SCH and/or the UL-SCH, e.g., forthe downlink and/or uplink, respectively.

TrCH may include an augmented set of requirements supported by the airinterface and/or support for one or more, or multiple, transportchannels (e.g., for user and/or control plane data) for one or more WTRUdevices. TrCH may have a different and/or broader meaning than a similarterm for previous generations, such as LTE systems. For example, atransport channel for URLLC (e.g., URLLCH), for mobile broadband (MBBCH)and/or for machine type communications (MTCCH) may be defined fordownlink transmission (e.g., DL-URLLCH, DL-MBBCH and/or DL-MTCCH) and/orfor uplink transmissions (e.g., UL-URLLCH, UL-MBBCH and/or UL-MTCCH).

For example, one or more, or multiple, TrCHs may be mapped to adifferent set of physical resources (e.g., PhCH) belonging to the sameSOM. This mapping may be advantageous, for example, to supportsimultaneous transmission of traffic with different requirements overthe same SOM. For example, a URLLCH may be transmitted along MTCCHsimultaneously, for example, when a WTRU may be configured with a SOM(e.g., a single SOM).

A WTRU may be configured with one or more parameters associated with acharacterization of how data may be transmitted. A characterization mayrepresent constraints and/or requirements that a WTRU may be expected tomeet and/or enforce. A WTRU may perform different operations and/oradjust its behavior as a function of the state associated with databased on a characterization. Parameters may include, for example,time-related aspects (e.g., such as Time to Live (TTL) for a packet(e.g., on a per-packet basis), which may represent the time before whichthe packet can be transmitted to meet, and/or acknowledge, etc. to meetlatency requirements), rate-related aspects and/or configuration relatedaspects (e.g., absolute priority). Parameters may be changed with time,for example while the packet and/or data may be pending fortransmission.

A number of protocol architectures may support the functions listed. Forexample, HARQ retransmissions may be handled. One or more SOM may beselected to perform retransmissions. A SOM may include a differentcarrier in the same and/or different band, a different RAT, and/or adifferent mode of 5G PHY. Further, the term logical channel (LCH) in thefollowing might not be associated to a traditional logical channel.

A WTRU may be configured with a (e.g., a single) HARQ entity. The WTRUmay have a (e.g., a single) HARQ buffer to manage for the HARQ signalsreceived across the SOMs. The WTRU may be configured to transmit/receivetraffic of any kind over any SOM. FIG. 10 illustrates an example mappingbetween LCH and one or more SOMs at a high level. For example, in FIG.10 there may be one (e.g., at least one) HARQ entity per WTRU.Retransmission can take place over any SOM.

FIG. 11 illustrates an example (e.g., a single) HARQ entity per WTRUtechnique in the context of a full protocol stack, and/or in the contextof the full functions of a protocol stack. This example protocol stackmay include (the example assumes MIP packets flows (and/or radiobearers) and N SOMs): header compression and/or security mechanism,security, segmentation/concatenation/ARQ,(de-)multiplexing/prioritization, HARQ/mapping to SOM/carrier, and/ormodulation, mapping to physical channel (PhCH)/SOM. The headercompression and/or security mechanism may take as input IP packetsand/or perform header compression and/or apply security (e.g., integrityprotection, ciphering), depending on the configuration. There may be asmany such blocks as there are radio bearers - M in this example.Security may be in another network node, e.g., further from the 5Gcell/TRP

Segmentation/concatenation/ARQ may be responsible for segmenting and/orconcatenating PDUs according to the radio resources available. The ARQfunctionality may ensure delivery. De-multiplexing/prioritization, onthe transmitting side (e.g., uplink for the WTRU), may be responsiblefor multiplexing one or more radio bearers PDUs together according torules and/or prioritize the transmission. The multiplexing and/orprioritization rules may be configured by higher layers. The output ofde-multiplexing/prioritization may be mapped to a SOM for transmission.Re-segmentation may be performed when needed. On the receiving side(e.g., downlink for the WTRU), de-multiplexing/prioritization mayde-multiplex the SDUs and/or push them to the propersegmentation/concatenation/ARQ entity. HARQ/mapping to SOM/carrier maycontrol the HARQ protocol and/or route to the proper SOM. The HARQentity may perform the physical layer retransmissions and/or may routethe PDUs to one or more, or any, SOM. In Modulation, mapping to PhCH/SOMmay map the coded bits to appropriate symbols mapped to the appropriateresource on the physical channel of at least one of the selected SOM(₁... _(N)).

A WTRU may be configured with a HARQ entity for one or more, or each,SOM configured. The logical channels may be assigned/mapped to any SOMs.Retransmission might not take place over one or more, or any, SOM. FIG.12 illustrates an example high level mapping between LCH and one or moreSOMs. One or more, or each, logical channel may be mapped to a SOM. ASOM may be associated with at least one (e.g., dedicated) HARQ entity.The WTRU may be configured to perform HARQ retransmissions within thesame SOM of the original transmission. ARQ retransmissions may becarried on a different SOM. The WTRU may select a (e.g., best) SOM(perhaps for example according to predefined criteria) at one or more,or each, moment of time for a given PDU. FIG. 13 illustrates an exampleof a (e.g., a single) HARQ entity per SOM technique in the context of afull protocol stack, and/or in the context of the full functions of aprotocol stack. The example protocol stack may include (the exampleassumes MIP packets flows (and/or radio bearers) and N SOMs) one or moreof: a header compression and/or security mechanism, security,segmentation/concatenation/ARQ, demultiplexing/prioritization,HARQ/mapping to SOM/carrier, and/or modulation, mapping to PhCH/SOM.Similar function(s) may performed as described herein with respect toFIG. 11 . The mapping to a SOM/Carrier may be carried out before theHARQ entity. There may be N HARQ entities, for example at least one forone or more, or each, SOM. One or more HARQ retransmissions may becarried out in the same SOM.

The LCH may be mapped to a SOM using predefined rules. The mapping maybe based on the requirements for the various type of traffic and/or oneor more SOM capabilities. For example, a 10 ms TTI SOM might not be ableto reach a 1 ms latency requirement, and/or might not be assigned to thechannel carrying that traffic. FIG. 14 illustrates an example high levelmapping between LCH and SOMs. For example, at least one HARQ entity maybe allocated per SOM. A LCH may be mapped to one or more, or a single,SOM.

FIG. 15 illustrates an example of a (e.g., a single) HARQ entity per SOMtechnique in the context of a full protocol stack, and/or in the contextof the full functions of a protocol stack. As shown, an example protocolstack may include (the example assumes M IP packets flows (and/or radiobearers) and N SOMs): header compression and/or security mechanism,security, segmentation/concatenation/ARQ,de-multiplexing/prioritization, HARQ/mapping to SOM/carrier, and/ormodulation, mapping to PhCH/SOM. Similar function(s) may performed asdescribed herein with respect to FIG. 11 . Although located belowsegmentation/concatenation/ARQ, the mapping to SOM/Carrier block may belocated higher in the stack, even before header compression/security.After the mapping to SOM/carrier, the WTRU may configured with at leastone set of one or more, or each, block for one or more, or each, SOM.The WTRU may perform prioritization on a per-SOM basis. The WTRU maydetermine the traffic priority for a (e.g., one or more, or each) SOMindependently. ARQ retransmission may be carried out in the same SOM.The WTRU may be configured by higher layers (e.g., RRC signaling and/orother) with the SOM for a (e.g., one or more, or each) radio bearer.

A radio bearer may be mapped to one or more SOMs. The WTRU may beconfigured with, for one or more, or each, radio bearer, a set of SOMsit may use. The WTRU may dynamically determine, based on radioconditions, buffer status and/or other parameters, the SOM to use.

Temporary upgrade and/or downgrade of a LCH may be performed. An LCHand/or a radio bearer may maintain its general characteristics (e.g.,priority, and/or bandwidth requirements, etc.), but may be upgraded to ahigher priority and/or lower latency SOM, e.g., for a temporary periodof time. Specifically, a service may have specific characteristics ingeneral, but may have its service “temporarily upgraded”. A logicalchannel may be moved to a different SOM for the period of time in whichit is temporarily upgraded. The underlying PHY treatment of the sameradio bearer/logical channel may be changed.

Multiplexing, prioritization and/or mapping to SOMs/TrCH of data fromdifferent logical channels may be performed. The creation of a MAC PDUand/or prioritization process may be initiated based on one or moretriggers.

A WTRU may perform autonomous transmissions under certain situations,such as when time critical data has arrived at the WTRU which supersedesother ongoing (cell scheduled) transmissions. The WTRU might not beprovided with the size and/or transport block parameters to be used bythe cell. In response to a trigger in the MAC layer and/or from upperlayers, the WTRU may multiplex one or more higher layer SDUs that mayrequire immediate transmission into one or more MAC PDUs to be sent tothe PHY layer for transmission. The autonomous creation of a transportblock may be triggered by one or more of: the arrival of a time criticalpacket at the MAC layer and/or higher layers, the QoS-based parameterassociated with one or more packets and/or data falling below athreshold, periodically (e.g., upon expiry of a timer), upon creationand/or (re)configuration of a latency critical and/or other service,and/or creation and/or (re)configuration of an SOM, based on anindication from the MAC layer and/or upper layers one of its buffers isno longer empty, and/or based on buffer occupancy information from theMAC layer and/or higher layers, and/or the HARQ entity indicatingretransmission of a MAC PDU may be useful.

The WTRU may receive a trigger one or more, or each, time a low-latencySDU currently in its buffer has its time to live (TTL) that may becomelower than a specific threshold. The WTRU, at the time of MAC PDUcreation, may select the SDUs for which the TTL is below a thresholdand/or multiplex them into the same MAC PDU. If a restriction related tothe mapping of logical channels to transport channels exists, the WTRUmay create separate MAC PDUs to send to the PHY layer while respectingthese restrictions. The WTRU may (e.g., periodically, perhaps based on atimer) select the MAC SDUs for which the TTL may be below a thresholdand/or perform multiplexing of these SDUs onto one or more MAC PDUs.

Mapping and/or multiplexing of LCH to TrCH/SOMs may be performed. TheWTRU may be configured to transmit data from the different logicalchannels on the different SOMs on the uplink. One or more, or multiple,logical channels may be transmitted together in a (e.g., a single)transport channel (TrCH). The WTRU may be configured to receivescheduling information from the network indicating which logical channelto map to one or more, or each TrCH and/or SOM. The WTRU may (e.g.,autonomously) determine the transmission parameters (including the SOMsand/or the multiplexing) dynamically.

Multiplexing and/or prioritizing one or more, or multiple, LCH to one ormore, or each TrCH/SOMs may be performed. At least one LCH may beassociated with at least one SOM. The term SOM and TrCH may be usedinterchangeably herein. A TrCH may be associated to the same SOM. Whilesome of the techniques are described in the context of associating ormapping a LCH to a SOM, similar techniques may also be applicable forthe multiplexing of one or more, or multiple, LCHs.

The WTRU may determine the transmission parameters based onpre-determined transport and/or service types. The MAC layer of the WTRUmay multiplex a specific set of logical channels and/or service types toa set of distinct transport channels in such a way that a set of logicalchannels and/or services can (e.g., only) be mapped to specifictransport channels. The WTRU may then create transport blocks and/ordata blocks to be transferred to the PHY layer in such a way that agiven transport channel may receive (e.g., receive only) data associatedto the logical channels which can be mapped to that transport channeland/or that SOM.

The mapping between logical channel and associated transport channel maybe defined statically based on a standardized mapping. For example, aset of transport channels T1, T2,... TN may correspond to differentlevel of service, quality of service, and/or guarantee of serviceprovided by the PHY layer. A set of logical channels L1, L2,... LM maybe defined. The WTRU MAC layer may receive one or more packets fromhigher layers that may be identified to be part of a specific servicetype S1, S2... SM. A WTRU may, based on a standardized mapping,multiplex certain logical channels to a specific transport channel. Forexample, L1, L2 may be multiplexed onto T1, L3 may be multiplexed ontoT3, etc. Packets with service type S1, S2 may be sent on T1, packetswith service type S3 may be sent on T2, etc.

The WTRU may determine the transmission parameters based on servicetype, e.g., ultra-reliable and/or low latency communication (URLLC),MTC, eMBB, etc. One or more specific transport channel may be associatedwith the logical channel/flows/services associated with ultra-reliablecommunications. Certain transport channel(s) may be associated with lowlatency communications. Certain transport channel(s) may be associatedto machine type communication (MTC). Certain transport channel(s) may beassociated to mobile broadband communication (MBB). Certain transportchannel(s) may be associated to WTRU control information, and/or a lastset of transport channels may be associated with one or more, or all,other communications. The mapping between logical channel/flows/servicesand transport channels may follow the rules of the association.

The WTRU may determine the transmission parameters based on mappingconfiguration on a per-SOM basis. The mapping of logical channels and/orservice types to transport channels may be configurable by the network,e.g., through broadcast or dedicated signaling, and/or through the useof the access table by the WTRU.

Mapping of a multiplexing list may be performed on a per-SOM basis. Forexample, a multiplexing list may be mapped to SOM. For one or more, oreach, LCH in one or more, or each, SOM a multiplexing list configurationmay be generated. The WTRU may be configured (e.g., via higher layerand/or RRC signaling) with a set of multiplexing rules. The WTRU may beconfigured for one or more, or each, LCH with the set of (e.g., allowed)SOM it may be mapped to. The WTRU may be configured, for one or more, oreach, SOM and/or one or more, or each LCH, with the set of (e.g., other)one or more LCH with which it may be multiplexed in a TrCH. The networkmay allow one or more (e.g., certain) LCH to be multiplexed in a SOMperhaps for example while not in a different SOM in some scenarios.

The WTRU may determine the transmission parameters/data transferparameters, perhaps for example based on meeting LCH requirements, amongother scenarios. The WTRU may be configured with a set of requirementsfor one or more, or each LCH. These requirements may include, forexample, one or more of: latency and/or maximum delay, reliability,average bit rate, guaranteed bit rate, traffic and/or service type(e.g., Ultra-Low Latency/Ultra-High Reliability, MTC, eMBB, voice, videostreaming, control information, etc.), and/or QCI, and/or the like.

The WTRU may be configured, and/or may determine on its own, the set ofcharacteristics/capabilities of a configured SOM. These characteristicsmay include, for example, of one or more of: TTI duration, bandwidth,symbol rate, coding characteristics (e.g., a rate, a reliability, and/orthe like), set of supported modulation and coding scheme (MCS), HARQparameters (e.g., maximum number of retransmissions, incrementalredundancy vs chase combining), subcarrier spacing, waveform and/orassociated parameters (e.g., cyclic prefix length, guards, preamble,etc.), spectrum license mode (e.g., licensed, unlicensed, lightlylicensed), a type of connectivity (e.g., device-to-device (D2D), and/orwide area network (WAN)), relay or direct, destination and/or TRPreceiver point, set(s) of supported traffic types, and/or set(s) ofsupported QCI (and/or similar QoS index metric), etc.

The WTRU may determine set of LCH that may be multiplexed together in agiven transport block in a given SOM. For example, the WTRU maydetermine the mapping of one or more, or each, LCH to SOM, perhaps basedon the LCH requirements and/or the SOM characteristics. The WTRU maydetermine, for an LCH, whether the characteristics of a certain SOMmeets the LCH requirements. The WTRU may determine a (e.g., a single)SOM for an (e.g., one or more, or each) LCH. The WTRU may determine, forone or more, or each, LCH, the set of SOMs that may meet the one or moreLCH requirements.

For example, the WTRU may compare the latency requirement of a LCH andthe minimum latency of a SOM based on e.g., the TTI length, the HARQfeedback delay, and/or other parameters and/or determine if the SOMmeets the latency requirement. In such scenarios, among others, the WTRUmay determine that the LCH may be mapped to that particular SOM. Forexample, the WTRU may compare the bit rate requirement for a specificLCH to the maximum bit rate achievable by a SOM (e.g., by the maximumMCS and/or available and/or configured bandwidth) and/or may map the LCHto the SOM, perhaps for example if it meets the requirement.

The WTRU may determine the mapping of LCH to SOM based on compatibleproperties of LCH, SOM. The WTRU may determine the mapping of LCH to SOMbased on compatible LCH requirements and/or one or more SOMcharacteristics, for example using one or more of therequirements/characteristics described herein. The WTRU may multiplexLCH to the same SOM based on destination.

The WTRU may determine the mapping of LCH to SOM based on thedestination associated to one or more, or each, logical channel. Forexample, some logical channels may be associated with D2D transmissionto a particular device (e.g., L2 address). For example, an LCH may beassociated with a particular TRP. The WTRU may configure LCH associatedto the same destination (e.g., D2D, TRP, and/or other) to the associatedSOM.

The WTRU may determine the mapping of LCH to SOM based on a set of QoSClass Identifier (QCI) supported. The WTRU may be configured with a setof support QCI for an (e.g., one or more, or each, SOM). The WTRU maydetermine the set of SOM for one or more, or each, LCH, perhaps forexample based on the configured LCH QCI. The WTRU may determine that aLCH may be mapped to a SOM when (e.g., only when) there is an exact QCImatch. The WTRU may be configured to determine the set of SOM that atleast meet the QCI of the LCH.

The WTRU may determine the mapping of LCH to SOM based on traffic typesupported. The WTRU may be configured with a set of traffic typesupported for one or more, or each, SOM. The WTRU may determine themapping of one or more, or each, LCH to SOM, perhaps for example basedon the LCH traffic type. For example, a SOM may be configured to supportbest effort traffic (e.g., 60 GHz, unlicensed). The WTRU may map besteffort LCHs to that SOM and/or map other type of traffic (e.g.,conversational voice, ultra-high reliability and/or other) to adifferent SOM (e.g., in the 2 GHz band, for example).

Mapping of LCH to SOM/TrCH may be performed dynamically. Transportchannel may be selected based on transport layer state/propertyinformation. A WTRU may select from one or more (e.g., available)transport channels (e.g., T1 and/or T2) for which a specific logicalchannel can be mapped onto and/or onto which a specific higher layerpacket may be transmitted. The WTRU may make such determinations basedon a dynamic state of the transport channel (e.g., at a given time),and/or the MAC entity information. The information may include one ormore of: the current occupancy of the logical channel(s) (and/or queuesassociated with one or more, or each, logical channel) being considered,QoS-based parameter associated with the data in a given logical channel,such as TTL of a packet the TTL of a set of packets, and/or the TTLrelative to a threshold, and/or the size of a packet and/or group ofpackets.

FIG. 16 illustrates an example of a WTRU (e.g., a WTRU processor and/orcontroller) dynamically matching data units to TrCH that may meet theQoS requirement of the data units. One or more, or each, data unit mayhave its own QoS requirement (QoS_1, QoS_2, etc.). In some scenarios,one or more data units can have the same QoS requirement. The Data Unitrequirements may include one or more of: latency, reliability, data rateand/or Transport block size, and/or QCI, etc. The WTRU may be configuredwith one or more, or multiple, transport channels, one or more, or each,with their own characteristics in terms of one or more of: numerology(e.g., which may include a subcarrier spacing and/or an associatedsymbol duration), MCS, coding rate, TTI duration, reliability, HARQretransmission, and/or delays, etc.

The WTRU may determine for one or more, or each, data unit the targetTrCH by matching the requirements to the TrCH capabilities. This mayensure that the requirements for the data unit are met, perhaps at leastto a satisfactory degree. In FIG. 16 , data units from the LCH_(M) maybe mapped to TrCH_(N). A (e.g., specific) data unit of LCH₁ with QoS₂may also be routed to TrCH_(N), for example because its QoS requirement(e.g., QoS₂) might not be met by TrCHi in this scenario. The LCH₁ andLCH_(M) data units (e.g., such as those mapped to TrCH_(N)) may bemultiplexed together, perhaps for example if the data units havesufficiently compatible QoS requirements (e.g., within a determinedand/or preconfigured difference tolerance and/or threshold).

The WTRU may send a transmission of a one or more, or multiple, uplinkdata units. For example, the WTRU may send a transmission of a firstuplink data unit and a second uplink data unit. The WTRU may identify afirst Quality of Service for the transmission of the first uplink dataunit. The WTRU may identify a second QoS for the transmission of thesecond uplink data unit. The WTRU may determine that a differencebetween/of the first QoS and the second QoS is within a preconfiguredthreshold, or outside the preconfigured threshold. The WTRU maymultiplex the second uplink data unit with the first uplink data unit inthe transmission, perhaps for example when the difference between/of thefirst QoS and the second QoS is within a preconfigured threshold. Thesecond uplink data unit maybe multiplexed with the first uplink dataunit in the transmission, perhaps for example up to a preconfiguredmultiplex ratio (as described herein).

The WTRU may receive such dynamic transport layer state information fromthe PHY layer. For instance, the MAC layer may make its determination ofmapping based on information dynamically provided by the PHY layerand/or statically associated with a specific transport channel and/ortransport channel type. Such information may include one or more of: theamount of PHY resources available for a specific transport channel, thetype of PHY resources available for the transport channel (e.g.,contention based vs. dedicated, and/or TTI used by the transportchannel), HARQ information, such as HARQ process type, number orprocesses, occupancy of one or more, or each, process, and/or status ofthe available HARQ processes (e.g., pending TX or re-TX) of theassociated transport channel, SOM over which the transport channel ismapped, and/or a maximum transport block size supported for a transportchannel and/or currently allowed for the transport channel.

One or more transmission channels may be reserved for retransmissions.One or more special transport channels may be reserved specifically forthe purpose of retransmission by the WTRU. The WTRU may, upon failedtransmission of a PDU at a layer (e.g., MAC/RLC/etc.), retransmit thatPDU using at least one of the reserved transport channels. Thesetransport channels may have specific PHY/MAC properties, including,shorter TTI, and/or HARQ process type allowing more HARQre-transmissions within a shorter period of time, higher coding rate,lower modulation scheme, and/or larger transmission power.

Incompatible multiplexing of LCH may be avoided or reduced. The WTRU maydynamically determine which set of LCH from the set of allowed LCH maybe multiplexed together in an actual transport channel. As used herein,the term “multiplexing” may be equivalent to the term“segmentation/assembly” and may be used interchangeably.

The transmission characteristics of a larger amount of data may bedetermined based on the latency requirement associated with a smallamount of data. For example, an LCH with low latency requirement may bemultiplexed with a logical channel with much larger latency requirement.LCHs associated with much different reliability requirement may bemultiplexed.

Multiplexing restrictions may be imposed based on logical channels. Forexample, a WTRU may perform segmentation/assembly across (e.g., onlyacross) MAC SDUs that are associated with a specific logicalchannel/service type/priority. For example, the MAC layer may performseparate segmentation/assembly operations on SDUs coming from logicalchannels and/or upper layer services associated with ultra-low latency,and a different segmentation/assembly operation on SDUs associated withhigh reliability transmissions.

SOM/transport channel for transmission of control information may beselected and/or multiplexed. The MAC layer may transmit different typesof control information over different underlying transport channelsand/or PHY resource types. For example, a MAC CE may be of differenttypes. Perhaps for example depending on the MAC CE type, a WTRU maydetermine whether to transmit such a MAC CE on a given transportchannel, and/or multiplex a MAC CE with a specific set of MAC SDU and/orSDU segments.

For example, the WTRU may have a different MAC CE for transmission ofbuffer status report (BSR) associated with its low-latency logicalchannels. A WTRU may transmit a CE such as a “ULL MAC CE” over (e.g.,only over) the dedicated ULL transport channel (for example, bypiggybacking the MAC CE on a transport block containing a ULL MAC PDU).Such a restriction may, however, allow for non-ULL MAC CEs to still besent with ULL resources, and/or may require them to be sent using (e.g.,only using) the non-ULL transport block resources.

For example, high priority MAC CEs may associated with (e.g.,exclusively with) a transport channel dedicated for transmission of suchinformation. The transport channels may, for example, be associated withdedicated PHY resources.

WTRU may multiplex LCH(s) with requirements up to a certain fraction ofprimary LCH. For example, the WTRU may be configured with a set ofparameters controlling the amount of data of varying requirements thatcan be multiplexed together.

The WTRU may determine a primary LCH and an associated primary LCH set.The primary LCH may be selected by the WTRU based on the priority (e.g.,using techniques described herein). The WTRU may determine theassociated primary LCH set that may include LCH(s) with the same orsimilar requirements as the primary LCH and/or may be multiplexed withit according to WTRU configuration. The primary LCH set may beconfigured by the network (e.g., similar to a multiplexing list) and/ormay be determined by the WTRU based on the requirements for the LCHs.The primary LCH may belong to the primary LCH set. The WTRU maydetermine a non-primary LCH set that may include the set of LCH thatmight not be part of the primary LCH set and/or may be multiplexed withthe primary LCH.

The WTRU may be configured with a ratio ρ indicating the maximum amountof data from the non-primary LCH set that may be allowed to bemultiplexed with a chosen primary LCH set in a given transport block.For example, if the WTRU has determined that Np bits from the primaryLCH set are to be transmitted in a certain transport block, the WTRU maymultiplex up to N non-p <ρ × Np bits from non-primary LCH set in thesame transport block. For embodiment, the non-primary LCH and/or primaryLCH may include (e.g., only include) LCH(s) for which data is availablein the associated buffer.

The WTRU may multiplex LCH(s) based on their associated data type(s).The WTRU may multiplex LCH(s) such that the differences in data type maybe minimized. The WTRU may select MAC SDUs for assembly in such a waythat the MAC PDU has a minimum percentage of data of a specific type(e.g., logical channel type, service type, latency requirement, etc.) sothat the MAC PDU may be associated with that type. For instance, theWTRU may ensure that the maximum possible number of low-latency SDUsand/or SDU segments are assembled together, and/or minimize the numberof non-low-latency segments that are assembled together with low-latencysegments.

The WTRU may associate a logical channel, a MAC SDU and/or SDU segment,with a specific multiplexing category and/or class. The category and/orclass may be associated with any combination of, logical channel, typeof data (time critical vs high reliability requirements vs highefficiency requirements), strictness of latency requirement ofassociated data, and/or QoS-based parameter related to data. The WTRUmay create a MAC PDU such that a certain minimum percentage of datawithin the PDU are associated with that category and/or class (forexample - 60% of data associated with time critical data where TTL maybe below a specific threshold). Low-latency MAC SDU segments may bemostly placed in PDUs that are primarily composed of low-latency data.The underlying PHY layer may treat such MAC PDUs with higher priority.The category and/or classes may be defined in a dynamic manner. Forexample, based on the current data to be transmitted, the WTRU maycreate the specific conditions that may define the class.

The WTRU may multiplex LCH and/or SDUs based on latency characteristics(e.g., TTL Ranges). The WTRU may perform multiplexing of MAC SDUs bytaking into account the latency characteristics associated with the SDU,and/or associating the MAC SDUs that may satisfy a specific QoS-basedcharacteristic together.

For example, the WTRU may, perhaps when creating a MAC PDU, assemble MACSDUs and/or MAC SDU segments that may have the same TTL. The WTRU may,when creating a MAC PDU, assemble MAC SDUs and/or MAC SDU segments thatmay have TTLs that may differ by not more than a threshold between eachother. The resulting MAC PDUs (and/or effectively transport blocks) maybe ordered in terms of TTL and/or TTL range.

The WTRU may multiplex LCH(s) with differences in latency requirements.For example, the WTRU may multiplex and/or transmit in the sametransport block data packets for which the latency requirements is noless than ΔLatency away. Parameter/variable ΔLatency may be a fixedvalue configured by the network and/or fixed in the specifications.Parameter/variable ΔLatency may be dynamically and/or semi-dynamicallysignaled to the WTRU.

The WTRU may multiplex LCH(s) and/or SDUs based on TTI Duration to beutilized in PHY layer. The WTRU may perform segmentation/assembly of MACSDUs based on the TTI to be utilized for transmission over the PHYlayer. The WTRU may associate a MAC SDU and/or a logicalchannel/flow/service with a (e.g., specific) TTI. The SDUs may beassembled/segmented, in such a way that the (e.g., one or more, or all,)SDU segments to be used in creating a MAC PDU may utilize the same TTIvalue. The SDU segments may effectively be the TTI duration with whichthe PHY layer transmits the PDU. The TTI to be associated with aspecific MAC SDU could be determined by the WTRU. For example, the TTImay be associated, statically and/or dynamically through signaling bythe cell and/or based on some internal state of the WTRU, with thelogical channel/service type of the data in the MAC SDU. For example, aspecific logical channel and/or any logical channel may be configured toutilize a specific TTI value. For example, the TTI to be utilized may bedefined by the PHY layer information, (e.g., in combination withpotentially other methods). For example, the PHY layer could indicate ata given time instant, and/or during a period of time, that TTI of 0.5 msis available and/or may be used for the logical channel groups withindex x and/or larger. For example, the TTI may be defined by theQoS-based parameter associated with the logical channel. For example, ifthe TTL for an SDU is below a threshold x, the WTRU may utilizetwo-symbol TTI. If the TTL is above threshold x, but below threshold y,the WTRU may utilize TTI 0.5 ms, and so on. The WTRU may include SDUsassociated with a different TTI in the associated grant, once thepending SDUs with the current TTI value have been included.

The WTRU may send one or more, or multiple, transport blocks (TBs) ofLCH with different requirements using one or more, or multiple, TrCHs.Data of largely varying requirements may be transmitted simultaneously.The WTRU may transmit one or more, or multiple, transport blocks (e.g.,simultaneously) each on its own TrCH.

Based on specific scheduling decision made by the WTRU (e.g., TTL,logical channel prioritization (LCP), and/or buffer occupancy, of suchrules), the WTRU may schedule more than one set of data with highlyvarying characteristics and/or having very different service type,and/or requirements, etc. The WTRU may transmit the MAC PDUs associatedwith such different service types using different transport formats. TheWTRU may transmit the different transport blocks using the same grantfrom the cell, and/or the same semi-static resources provided to theWTRU.

The WTRU may receive (dynamically and/or semi-statically) a grant thatmay indicate a set of available PHY resources (number of transportblocks, and/or the like). The WTRU may receive an indication on theradio quality of such resources, for example via downlink channel stateinformation (CSI) feedback. The WTRU may make an autonomous decisionabout the transport format to utilize when transmitting on theseresources (e.g., based on the radio quality associated with theresources).

The WTRU may divide the grant spectrum for one or more, or each, TrCH.The WTRU divide the PHY resources into distinct portions to beassociated with one or more, or each, of the transport blocks to betransmitted. The WTRU may restrict the division based on specific rulesassociated with specific association of carriers, resource blocks, orthe like. For instance, the WTRU might not be allowed to divide aresource block between two different transport blocks to transmit. TheWTRU may associate a different transport format (MCS, HARQ type, TTI,retransmission rules, etc.) with one or more, or each, of the transportblocks to be transmitted simultaneously. The WTRU may indicate to thecell the specific transport formats utilized in a transmission. Suchsignaling may be included within the transmission itself (e.g., based onmethods described herein). The WTRU may include such signaling in adedicated control channel used for UL PHY signaling.

The traffic types may be prioritized in the MAC for transmission for UL.Traffic may be associated with different latency requirement, may bemapped to different SOMs, and/or may have different reliabilityrequirement(s).

The WTRU may prioritize traffic based on the associated latencyrequirements. For example, a WTRU may select MAC PDUs to be scheduledfor transmission based on the time criticality of the data, and/or thetime available for the data in the MAC PDU before the data is consideredto have missed its timing requirements. For instance, a WTRU may selectMAC PDUs for transmission based on the QoS-based parameter value and/orthe range associated with the MAC PDU, and/or potentially assigned tothat MAC PDU by the WTRU.

At a specific scheduling instant and/or TTI, and/or at the specific timein which a PHY resource becomes available to the WTRU, the WTRU mayselect the pending MAC PDU having the smallest TTL and/or TTL rangeamong the pending MAC PDUs. The WTRU may select one or more, ormultiple, available PDUs for transmission, perhaps for example at thesame time instant, and/or substantially at the same time. The WTRU mayselect, of the buffered PDUs, those with the smallest TTL and/or TTLranges.

The WTRU may perform assembly in combination with the schedulingcriteria described herein. For example, the WTRU may, in satisfying agrant and/or available resource for transmission, select the MAC SDUswith the smallest TTL and/or perform multiplexing/assembly perhaps forexample in order to include the MAC SDUs having the lowest TTLs of thepending MAC SDUs.

The WTRU may perform such scheduling decisions on a subset of transportchannels, SOMs, and/or the like. For example, the WTRU may perform suchscheduling decisions in (e.g., only in) transmission to a subset and/orTRPs. The WTRU may perform such scheduling decisions when (e.g., onlywhen) being provided a grant for resources on a specific transportchannel and/or SOM (for example, associated with ULLRC transmission).

The WTRU may prioritize traffic based on PHY layer providing TTI ofgrant. For example, the MAC layer may perform its scheduling decisions,based on the TTI that may be provided by the PHY layer. The MAC layermay receive along with the information for a transmission grant, the TTIwith which the transmission may take place. The WTRU may select the MACSDUs to be multiplexed onto the MAC PDU based on knowledge of this TTI.For instance, if a short-TTI grant is provided, the WTRU may select theMAC SDUs associated with logical channels that may be for low-latencytransmission. The WTRU may select the MAC SDUs for which the TTL may bebelow a specific threshold. The WTRU may receive one or more, ormultiple, grants that may apply at different TTIs and/or for differentTTI lengths.

The MAC layer may dynamically select and/or determine the TTI length tobe used to transmit a MAC PDU. Such determination may be made by theWTRU on the TTI and/or scheduling instant itself. The determination maybe made sometime in advance of the TTI, for a period of time, and/or fora set of resources for which the WTRU MAC has been informed of availableresources.

The WTRU may receive an indication of certain resources and/or resourcesets where the MAC layer may select the TTI. The WTRU may select, basedon scheduling decisions and/or prioritization rules, the data to betransmitted on the resources with shortened TTI. The determination maybe such that the data with time critical requirements can be transmittedin the time required when taking into account potential retransmissions.For example, the MAC layer may receive an indication (potentially frominformation from the PHY layer) of the location and/or amount ofresources for which shortened TTI may be utilized. The MAC layer mayreceive an indication of the current data to be transmitted and/or theTTL associated with this data. The MAC layer may schedule transmissionsbased on this information by ensuring that the latency criticaltransmissions are performed successfully. The specific TTI to use for aspecific MAC PDU might not be restricted. The transport block size forsuch planned transmissions may be driven by the amount of resources thatmay be associated with shortened TTI in the next subframe, frame, and/orlonger period of time.

Logical channel prioritization may be performed for multiplexing of timecritical data with non-time critical data - partially using legacy LCP.Different logical channel types (e.g., low latency, ultra-reliable, MBB,etc.) can be multiplexed onto the same MAC PDU, the WTRU may firstselect MAC SDUs that may be time critical for inclusion into a MAC PDUbefore performing the legacy LCP procedure.

Specifically, the WTRU may determine the MAC SDUs for which areconsidered time critical. This determination may be based on one or moreof: the TTL associated with the SDU is below a threshold, the TTLassociated with the SDU that is below a threshold has expired, the SDUcomes from a specific logical channel and/or flow identified by the WTRUfor being latency critical, the size of the SDU is below a specificthreshold, and/or the SDU has already been transmitted (e.g.,unsuccessfully) in a previously transmitted PDU and may represent aretransmission.

The WTRU may include the selected SDUs into the MAC PDU to transmit. TheWTRU may include the SDUs in order of some specific criteria, such as aQoS-based parameter, size, and/or logical channel priority. If the sizeof the MAC PDU is insufficient to include the time-critical SDUs, theWTRU may perform one or more of: including up to the number of SDUswhich fit in the MAC PDU by respecting a potential ordering ofinclusion, triggering the PHY layer to transmit a request for furtherresources and/or include a request for further resources (e.g., a PHYlayer indication for more resources) with the transmission of this MACPDU, including a BSR and/or similar MAC CE in the MAC PDU to indicatethis condition to the cell, triggering an autonomous transmission at theWTRU, which may include additional time-critical SDUs, and/or include arequest for resources, and/or triggering the PHY layer to utilize ashortened TTI for transmission of this MAC PDU.

The WTRU may perform legacy LCP to serve the logical channels up to thePBR. The WTRU may take into account the data selected in the secondstep, as having already been used when considering whether a logicalchannel has been served up to its PBR.

The WTRU may select MAC SDUs for the remainder of the MAC PDU accordingto one or more of: the logical channel priority, as per legacy LCP. TheWTRU may select one or more SDUs that may have a second level of timecriticality (for example, the TTL being above the first threshold, butbelow a second threshold).

The amount of data included in the MAC PDU while performing LCP maydiffer from the current LCP. The WTRU may select MAC SDUs for creationof a MAC PDU by selecting MAC SDUs from potentially different buffers(e.g., associated with logical channels, flows, services, etc.) in orderof time criticality. Time criticality may be measured, for example, byTTL. In other words, a WTRU could select SDUs in order of TTL, startingwith the smallest TTL and/or until the MAC PDU is filled.

The WTRU may select MAC SDUs for creation of a MAC PDU by selecting MACSDUs in order of time criticality (e.g., smallest to largest TTL) and/orimportance based on any QoS-based parameter until the MAC SDUs with acertain criticality are addressed (for instance, TTL less than athreshold). The remainder of the MAC PDU size can be used for, padding,control data (MAC CEs), and/or increasing the coding and/or redundancy.

The WTRU may select MAC SDUs for creation of a MAC PDU with some addedrestrictions on the logical channels/flows/services that it selects. Forinstance, the selection may be restricted to one or more of the logicalchannels, perhaps for example up to a specific threshold, before theother logical channels can be considered.

The WTRU may be configured, for one or more, or each, LCH, with apriority index. The priority index may be used, for example, todetermine the order in which PDUs of the same time delay requirement arescheduled. The priority index may indicate the order in which PDUs ofthe same type and/or class (e.g., best effort) are scheduled.

The WTRU may determine the order in which PDUs that do not meet theirlatency requirement may be dropped. More specifically, a WTRU may beconfigured to determine the order in which PDUs are transmittedaccording to (e.g., first according to) their delay requirement, and/oraccording to the priority order. If there are not sufficient resourcesto transmit the PDUs, then the WTRU may determine to drop PDUs withlower priority index (e.g., delete the PDUs from the buffer and/or notattempt transmission, as the packet has expired).

The WTRU may (e.g., autonomously) select transmission parameters.Transport format may be selected. For example, the WTRU may select thetransport format from a preconfigured list associated with traffic type,LCH, and/or SOM.

The WTRU (e.g., the MAC layer) may receive an indication of thetransport format(s) that may be usable for a specific grant. Forexample, a WTRU may be provided with a choice of transport formats to beused on a grant provided by the cell, and/or the WTRU may select theappropriate transport format and/or corresponding MAC PDU size based on,one or more of: the characteristics of data which the WTRU is planningto transmit (e.g., time-critical, reliability, high efficiency, etc.),the buffer status in the WTRU, potentially associated with one or more,or each, type of data, and/or QoS-based parameter associated with one ormore, or each, packet being selected.

Different transport formats may be associated with a service and/orservice type (e.g., ULRRC transport format (TF), and/or eMBB TF, etc.).The transport formats may be associated with different levels ofreliability (e.g., an error probability) and/or transmission rate.

The WTRU may associated with one and/or more, or each, transport formatsignaled by the cell with a service and/or service type. The associationmay be signaled as part of the transport formats themselves, for examplethrough an index and/or special field. The association may befixed/static and/or known previously by the eNB and/or WTRU. The WTRUmay choose its own association based on the characteristics of one ormore, or each, TF (e.g., more coding may be associated with morereliable communication). The WTRU may be given a range of servicesand/or service types to which it may associate a given TF.

The WTRU may be configured with a set of transport formats for one ormore, or each, SOM. The WTRU may determine the set of transport formatsto use based on the SOM to be used for transmission. The WTRU may, basedon the configuration, select the TF which matches the type of data to besent. Specifically, based on the services associated with the data(and/or majority of the data) in the MAC PDU, the WTRU may make the TFselection.

A WTRU, following selection of the transport format, may indicate theselected format to the cell in the transmission. The WTRU may providethis information as an index transmitted on a PHY-layer uplink controlchannel, such as PUCCH and/or a 5G control channel.

The WTRU may pre-pend/append to the uplink transmission (on the grantedresources themselves), an index which may be encoded using a predefinedand/or fixed mechanism. Such a transport format indication from the WTRUmay be present with the UL transmissions. The WTRU might not providesuch indication, and/or the cell may be required to before blinddecoding to determine the selected TF.

The WTRU may receive an indication of a specific TF in the grant, butmay determine to dynamically change the TF and/or inform the cell ofthis decision. The WTRU may be restricted to change the TF of the grant(e.g., only) on MAC PDUs that may contain data from specific logicalchannels and/or specific services. The WTRU may be restricted to changethe TF from the currently signaled TF to a finite set of “derived” TFswhich may have some specific relation to the original TF (thusfacilitating the signaling of the derived TF to the cell).

The WTRU may change the TF in order to add additional coding to databeing scheduled for example to increase robustness. The decision foradding additional coding may be based on one or more of: the reliabilityand/or latency requirements associated with the data that needs to besent, the QoS-based parameter associated with the data to be sent,and/or other data pending transmission, buffer occupancy, or lackthereof, and/or whether the MAC PDU is being re-transmitted, or whetherit is an initial transmission of the PDU.

The WTRU, perhaps for example after processing a certain number oflogical channels (e.g., up to the Prioritized Bit Rate (PBR)), and/or acertain number of MAC SDUs taking latency critical requirements intoconsideration), may determine to not include additional SDUs into theMAC PDU. The WTRU may indicate to the PHY layer to increase theredundancy (for example by reducing the code rate) associated with aspecific MAC PDU. For example, after the MAC SDUs having TTL below athreshold are included into the MAC PDU, and/or the logical channelshave been served up to the PBR, the WTRU might not include additionalMAC SDUs ready for transmission into the MAC PDU and/or may reduce thecoding rate (at the PHY layer) of the resulting MAC PDU.

A WTRU, perhaps for example following a re-selection of the transportformat, may indicate the selected format to the cell in the transmission(e.g., using at least one of the techniques described herein).

Although features and elements are described above in particularcombinations, one of ordinary skill in the art will appreciate that eachfeature or element can be used alone or in any combination with theother features and elements. In addition, the methods described hereinmay be implemented in a computer program, software, or firmwareincorporated in a computer-readable medium for execution by a computeror processor. Examples of computer-readable media include electronicsignals (transmitted over wired or wireless connections) andcomputer-readable storage media. Examples of computer-readable storagemedia include, but are not limited to, a read only memory (ROM), arandom access memory (RAM), a register, cache memory, semiconductormemory devices, magnetic media such as internal hard disks and removabledisks, magneto-optical media, and optical media such as CD-ROM disks,and digital versatile disks (DVDs). A processor in association withsoftware may be used to implement a radio frequency transceiver for usein a WTRU, UE, terminal, base station, RNC, or any host computer.

What is claimed is:
 1. A wireless transmit/receive unit (WTRU)comprising a processor and memory, the processor and memory configuredto: receive configuration information for a first logical channel and asecond logical channel, the configuration information indicating a firstset of one or more transmission requirements for the first logicalchannel and a second set of one or more transmission requirements forthe second logical channel; receive first downlink control information(DCI), the first DCI indicating a first resource allocated for a firstuplink transmission, wherein the first resource allocated for the firstuplink transmission is associated with a first type of hybrid automaticrepeat request (HARQ) process; determine to multiplex a first mediumaccess control (MAC) service data unit (SDU) of the first logicalchannel into a first transport block to be transmitted via the firstresource allocated for the first uplink transmission based on the firstset of one or more transmission requirements for the first logicalchannel indicating that the first type of HARQ process can be used fortransmission of data associated with the first logical channel, anddetermine not to multiplex a first MAC SDU of the second logical channelinto the first transport block to be transmitted via the first resourceallocated for the first uplink transmission based on the second set ofone or more transmission requirements for the second logical channelindicating that the first type of HARQ process cannot be used fortransmission of data associated with the second logical channel; andtransmit the first transport block including the first MAC SDU of thefirst logical channel via the first resource allocated for the firstuplink transmission.
 2. The WTRU of claim 1, wherein the processor andmemory are further configured to: receive second DCI, the second DCIindicating a second resource allocated for a second uplink transmission,wherein the second resource allocated for the second uplink transmissionis associated with a second type of HARQ process; determine to not tomultiplex a second MAC SDU of the first logical channel into a secondtransport block to be transmitted via the second resource allocated forthe second uplink transmission based on the first set of one or moretransmission requirements for the first logical channel indicating thatthe second type of HARQ process cannot be used for transmission of dataassociated with the first logical channel, and determine to multiplex asecond MAC SDU of the second logical channel into the second transportblock to be transmitted via the second resource allocated for the seconduplink transmission based on the second set of one or more transmissionrequirements for the second logical channel indicating that the secondtype of HARQ process can be used for transmission of data associatedwith the second logical channel; and transmit the second transport blockincluding the second MAC SDU of the second logical channel via thesecond resource allocated for the second uplink transmission.
 3. TheWTRU of claim 2, wherein the first type of HARQ process allows for ashorter retransmission period than the second type of HARQ process. 4.The WTRU of claim 3, wherein the first set of one or more transmissionrequirements for the first logical channel indicate that the firstlogical channel is associated with a first latency requirement, thesecond set of one or more transmission requirements for the secondlogical channel indicate that the second logical channel is associatedwith a second latency requirement, and the first latency requirement isshorter than the second latency requirement.
 5. A method implemented bya wireless transmit/receive unit (WTRU), the method comprising:receiving configuration information for at least one logical channel,the configuration information indicating one or more transmissionrequirements for the at least one logical channel; receiving downlinkcontrol information (DCI), the DCI indicating a resource allocated foran uplink transmission, wherein the resource allocated for the uplinktransmission is associated with a first type of hybrid automatic repeatrequest (HARQ) process; determining whether to multiplex a medium accesscontrol (MAC) service data unit (SDU) of the at least one logicalchannel into a transport block to be transmitted via the resourceallocated for the uplink transmission based on whether the one or moretransmission requirements for the at least one logical channel indicatethat the first type of HARQ process can be used for transmission of dataassociated with the at least one logical channel; and transmitting thetransport block via the resource allocated for the uplink transmission.6. The method of claim 5, wherein the one or more transmissionrequirements indicate that the first type of HARQ process can be usedfor transmission of data associated with the at least one logicalchannel, and the MAC SDU is multiplexed into the transport block.
 7. Themethod of claim 5, wherein the one or more transmission requirementsindicate that the first type of HARQ process cannot be used fortransmission of data associated with the at least one logical channel,and the MAC SDU is not multiplexed into the transport block.
 8. Themethod of claim 5, wherein the first type of HARQ process allows for ashorter retransmission period than a second type of HARQ process.
 9. Themethod of claim 5, wherein the first type of HARQ process is associatedwith a first spectrum operating mode (SOM), and a second type of HARQprocess is associated with a second SOM.
 10. The method of claim 5,wherein the resource allocated for the uplink transmission is furtherassociated with a transmission duration, and wherein determining whetherto multiplex the MAC SDU of the at least one logical channel into thetransport block is further based on whether the one or more transmissionrequirements for the at least one logical channel indicate that thetransmission duration can be used for transmission of data associatedwith the at least one logical channel.
 11. The method of claim 5,wherein the resource allocated for the uplink transmission is furtherassociated with a subcarrier spacing, and wherein determining whether tomultiplex the MAC SDU of the at least one logical channel into thetransport block is further based on whether the one or more transmissionrequirements for the at least one logical channel indicate that thesubcarrier spacing can be used for transmission of data associated withthe at least one logical channel.
 12. The method of claim 5, wherein theconfiguration information is received in a radio resource control (RRC)message.
 13. A wireless transmit/receive unit (WTRU) comprising aprocessor and memory, the processor and memory configured to: receiveconfiguration information for at least one logical channel, theconfiguration information indicating one or more transmissionrequirements for the at least one logical channel; receive downlinkcontrol information (DCI), the DCI indicating a resource allocated foran uplink transmission, wherein the resource allocated for the uplinktransmission is associated with a first type of hybrid automatic repeatrequest (HARQ) process; determine whether to multiplex a medium accesscontrol (MAC) service data unit (SDU) of the at least one logicalchannel into a transport block to be transmitted via the resourceallocated for the uplink transmission based on whether the one or moretransmission requirements for the at least one logical channel indicatethat the first type of HARQ process can be used for transmission of dataassociated with the at least one logical channel; and transmit thetransport block via the resource allocated for the uplink transmission.14. The WTRU of claim 13, wherein the one or more transmissionrequirements indicate that the first type of HARQ process can be usedfor transmission of data associated with the at least one logicalchannel, and the MAC SDU is multiplexed into the transport block. 15.The WTRU of claim 13, wherein the one or more transmission requirementsindicate that the first type of HARQ process cannot be used fortransmission of data associated with the at least one logical channel,and the MAC SDU is not multiplexed into the transport block.
 16. TheWTRU of claim 13, wherein the first type of HARQ process allows for ashorter retransmission period than a second type of HARQ process. 17.The WTRU of claim 13, wherein the first type of HARQ process isassociated with a first spectrum operating mode (SOM), and a second typeof HARQ process is associated with a second SOM.
 18. The WTRU of claim13, wherein the resource allocated for an uplink transmission is furtherassociated with a transmission duration, and wherein the processor andmemory being configured to determine whether to multiplex the MAC SDU ofthe at least one logical channel into the transport block is furtherbased on whether the one or more transmission requirements for the atleast one logical channel indicate that the transmission duration can beused for transmission of data associated with the at least one logicalchannel.
 19. The WTRU of claim 13, wherein the resource allocated for anuplink transmission is further associated with a subcarrier spacing, andwherein the processor and memory being configured to determine whetherto multiplex the MAC SDU of the at least one logical channel into thetransport block is further based on whether the one or more transmissionrequirements for the at least one logical channel indicate that thesubcarrier spacing can be used for transmission of data associated withthe at least one logical channel.
 20. The WTRU of claim 13, wherein theconfiguration information is received in a radio resource control (RRC)message.